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PubMed2006

Determinants of perinatal mortality and serious neonatal morbidity in the second twin.

OBJECTIVE: To identify potential determinants of perinatal mortality and neonatal morbidity among second twins relative to first twins. METHODS: A retrospective cohort design was used to study twin deliveries in Nova Scotia from 1988 to 2002. Monoamniotic or conjoined twins and twin pairs with major congenital anomaly or antepartum fetal death of either twin were excluded. The primary outcome was a composite measure of perinatal mortality and neonatal morbidity, including birth asphyxia, respiratory distress, neonatal trauma, and infection. Risk of adverse outcome of second twins relative to first-born co-twins was determined by matched-pair analysis. RESULTS: Of 1,542 twin pairs, the second twin was at greater risk of composite adverse outcome (relative risk [RR] 1.62, 95% confidence interval [CI] 1.38-1.9) than the first twin. This excess risk was evident independent of presentation, chorionicity, or infant sex but was associated with planned vaginal delivery, birth weight discordance, and prolonged interdelivery interval. Term second twins were less likely to suffer excess morbidity with elective cesarean (RR 1.0, 95% CI 0.14-7.10) than with planned vaginal delivery (RR 3.0, 95% CI 1.47-6.11). The major contributors to neonatal morbidity in the second twin were birth asphyxia at 37 weeks or later and respiratory distress syndrome at less than 37 weeks. CONCLUSION: The second twin is at greater risk of adverse perinatal outcome than the first twin, independent of presentation, chorionicity, or infant sex. Planned vaginal delivery, birth weight discordance, and prolonged interdelivery interval increase this infant risk. Elective cesarean delivery at term may improve perinatal outcome for the second twin. However, the number of cesarean births required to prevent one case of composite adverse outcome, assuming causality, was 33.

Adult↗
PubMed2003

Time course of brainstem pathophysiology during first month in term infants after perinatal asphyxia, revealed by MLS BAER latencies and intervals.

Dynamic changes in electrophysiology of brainstem auditory neurons during the first month after birth were studied in 51 term infants after perinatal asphyxia using maximum length sequence brainstem auditory evoked responses. The responses were recorded on d 1, 3, 5, 7, 10, 15, and 30 after birth. On d 1, wave III and V latencies and all interpeak intervals increased significantly at all repetition rates of clicks used (91-910/s), especially the higher rates (ANOVA, p < 0.05-0.0001). On d 3, all these latencies and intervals increased further and differed more significantly from the normal control subjects. Thereafter, the latencies and intervals decreased progressively. On d 7, wave V latency and all intervals still differed significantly from the control subjects. These dynamic changes were more significant at higher rates of clicks than at lower rates. On d 10 and 15, all intervals decreased significantly. On d 30, all wave latencies decreased to the values in the normal control subjects on the same day. The intervals also approached normal values, although the III-V and I-V intervals still increased slightly. These results indicate that hypoxic-ischemic brain damage persists during the first week, with a peak on d 3, and recovers progressively thereafter. By 1 mo, the damage has largely returned to normal. Maximum length sequence brainstem auditory evoked responses results correlated well with the stage of hypoxic-ischemic encephalopathy during the first week. The present study revealed a general time course of brainstem pathophysiology after asphyxia, although there were individual variations. Our findings can be used as a reference to monitor cerebral function and help judge the value of neuroprotective or therapeutic interventions. The first week, particularly the first 3 d, is a critical period of hypoxic-ischemic brain damage, and early intervention may prevent or reduce deterioration of the damage.

Asphyxia↗
PubMed2003

Effect of interpregnancy interval on infant low birth weight: a retrospective cohort study using the Michigan Maternally Linked Birth Database.

OBJECTIVE: To examine the relationship between interpregnancy interval and low birth weight (LBW), using the retrospective cohort design. METHODS: We used the maternally linked Michigan livebirth data documented between 1989 and 2000 to evaluate LBW in relation to interpregnancy (i.e., delivery-to-conception) interval, overall and at levels of other reproductive risk factors. We fit separate logistic regression models for pairs of first-second, second-third, third-fourth, and fourth-fifth births to control for confounding. RESULTS: Of the 565,911 infants identified, 5.5% had LBW. Univariate and stratified analyses showed that the risk for LBW was lowest when the interpregnancy interval was 18-23 months, and increased with shorter or longer intervals. This J-shaped relationship persisted after controlling for all risk factors simultaneously. For example, among the first-second birth pairs, the adjusted odds ratios (AORs) for LBW associated with interpregnancy intervals <6, 24-59, 60-95, and 96-136 months were 1.4 (95% confidence interval [CI] = 1.3-1.5), 1.5 (95% CI = 1.3-1.6), 1.1 (95% CI = 1.0-1.1) and 1.5 (95% CI = 1.3-1.8), respectively, compared with an interval of 18-23 months. Among the second-third birth pairs, the AORs were 1.5 (95% CI = 1.3-1.6), 1.3 (95% CI = 1.2-1.4), 1.1 (95% CI = 1.0-1.1), and 1.6 (95% CI = 1.3-2.0), respectively. Among the third-fourth birth pairs, the AORs were 1.2 (95% CI = 1.1-1.4), 1.3 (95% CI = 1.1-1.5), 1.0 (95% CI = 0.9-1.1), and 1.4 (95% CI = 1.0-2.0), respectively. Among the fourth-fifth birth pairs, the AORs were 1.3 (95% CI = 1.1-1.6), 1.2 (95% CI = 0.9-1.5), 1.1 (95% CI = 1.0-1.4), and 1.3 (95% CI = 0.8-2.3), respectively. The population attributable risk associated with interpregnancy intervals shorter than 18 months or longer than 23 months was 9.4%. CONCLUSION: These data suggest that spacing pregnancies appropriately could be used as a strategy for preventing LBW.

Adolescent↗
PubMed1994

The risk of repeating low birth weight and the role of prenatal care.

OBJECTIVE: To estimate the influence of adequacy of prenatal care and other known risk factors on the risk of repeating low birth weight (LBW) (less than 2500 g). METHODS: This was a retrospective cohort study of women having two births in Washington state during 1984-1990, as recorded using linked birth certificate records. Logistic regression was used to control for maternal age, marital status, smoking, miscarriage, inter-pregnancy interval, and prenatal care. RESULTS: Compared to the reference group of women with normal-weight first births (at least 2500 g), women with LBW first births, either preterm or small for gestational age (SGA), were significantly more likely to have an LBW second birth. The estimated relative risk of repeating LBW in general was 7.0 (95% confidence interval 4.8-10.1). Smoking during the second pregnancy was a significant effect modifier. The risk estimates were not significantly affected by any of the other variables entered into the models, including adequate prenatal care. CONCLUSIONS: Prior delivery of a preterm or SGA LBW infant was the strongest predictor of LBW delivery in a subsequent pregnancy. Adequate prenatal care during the second pregnancy did not provide statistically significant protection against the risk of repeat LBW. The tendency for women to have repeat LBW deliveries despite adequate prenatal care indicates a need for a better understanding of the underlying pathophysiology of preterm and SGA delivery.

Adult↗
PubMed2005

Delayed interval delivery in twin pregnancies in the United States: Impact on perinatal mortality and morbidity.

OBJECTIVE: To estimate the incidence of delayed interval delivery in twin pregnancies in the United States and evaluate the impact of delayed delivery on perinatal outcomes. STUDY DESIGN: A population-based retrospective cohort study was performed using the U.S. "matched multiple birth" file (1995 to 1998), restricting our analysis to twin sets in which the first twin was delivered vaginally at 22 to 28 weeks (n = 4257). Outcomes examined included perinatal and infant mortality and small-for-gestational-age births. Outcomes of second twins in pregnancies that underwent delayed interval delivery of 1, 2, 3, and >/=4 weeks were compared with those in which both twins were delivered contemporaneously. RESULTS: In this cohort, 6.1% (n = 258) of twins had delayed delivery (>/=1 week) of the second twin. Decreases in perinatal and infant mortality were observed only when the first twin was delivered at 22 to 23 weeks and when the delivery interval was </=3weeks. However, for intervals >/=4 weeks or when the first twin was delivered at 24 to 28 weeks (regardless of delivery interval), there was no benefit in perinatal or infant mortality. Delayed delivery of >/=4 weeks was associated with increased risk of small-for-gestational-age birth in the second twin, regardless of gestational age at delivery of the first. CONCLUSION: When a first twin was delivered at 22 to 23 weeks, delayed delivery of the second twin was associated with reduced perinatal and infant mortality of the second twin if the interval was less than 3 weeks. Delayed delivery of the second twin when the first was delivered at >/=24 weeks had no benefit on mortality.

Adult↗
PubMed2005

Baroreceptor reflex sensitivity in human neonates: the effect of postmenstrual age.

We performed a cross-sectional study in human infants to determine if indices of R-R interval variability, systolic blood pressure (SBP) variability, and baroreceptor reflex sensitivity change with postmenstrual age (PMA: gestational age+postnatal age). The electrocardiogram, arterial SBP and respiration were recorded in clinically stable infants (PMA, 28-42 weeks) in the quiet sleep state in the first days after birth. (Cross-)spectral analyses of R-R interval series and SBP series were performed to calculate the power of low-frequency (LF, indicating baroreceptor reflex activity, 0.04-0.15 Hz) and high-frequency (HF, indicating parasympathetic activity, individualized between the p-10 and p-90 values of respiratory frequency) fluctuations, and transfer function phase and gain. The mean R-R interval, and LF and HF spectral powers of R-R interval series increased with PMA. The mean SBP increased with PMA, but not the LF and HF spectral powers of SBP series. In the LF range, cross-spectral analysis showed high coherence values (>0.5) with a consistent negative phase shift between R-R interval and SBP, indicating a approximately 3 s lag in R-R interval changes in relation to SBP. Baroreceptor reflex sensitivity, calculated from LF transfer gain, increased significantly with PMA, from 5 (preterm) to 15 ms mmHg-1 (term). Baroreceptor reflex sensitivity correlated significantly with the (LF and) HF spectral powers of R-R interval series, but not with the LF and HF spectral powers of SBP series. The principal conclusions are that baroreceptor reflex sensitivity and spectral power in R-R interval series increase in parallel with PMA, suggesting a progressive vagal maturation with PMA.

Baroreflex↗
PubMed1991

Risk of IDDM in children of diabetic mothers decreases with increasing maternal age at pregnancy.

Offspring of women with insulin-dependent diabetes mellitus (IDDM) have a significantly lower risk of IDDM than the offspring of men with IDDM. Furthermore, a negative association of the risk of IDDM in the offspring with maternal age at delivery has been reported. This study tested the association with maternal age in an independent set of families (n = 103) in which the mother had at least one pregnancy before and after the onset of IDDM. In the 304 offspring, the mean +/- SE risk of IDDM by age 20 was 6.0 +/- 2.4% for those born at maternal ages less than 25 yr, whereas, the risk was significantly lower (0.7 +/- 0.7%) for those born at older maternal ages (P = 0.03). These 304 offspring were combined with a sample of 1391 offspring previously reported for a multivariate analysis of other factors related to pregnancy. In the combined analysis, the risk of IDDM in offspring born at maternal ages greater than 25 yr was one-fifth that for offspring born to younger mothers. The risk of IDDM in the offspring was not significantly related to birth order, mother's age at first pregnancy, or the interval between pregnancies for subsequent ones. The risk for the children born before the mother's onset of diabetes was higher than that for those exposed in utero to her diabetes, but the difference did not reach statistical significance. In conclusion, although genetic factors are important determinants of susceptibility to IDDM, exposure to maternal diabetes protects offspring from IDDM during the first 2 decades of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2000

Risk factors among young women with endometrial cancer: a Danish case-control study.

OBJECTIVE: This study was undertaken to identify and quantify risk factors for endometrial cancer among young women. STUDY DESIGN: This case-control study included all Danish women <50 years old who had endometrial cancer diagnosed during the period 1987 to 1994. A total of 237 case patients and 538 population control subjects matched with the case patients for age and residence were included in the analysis. RESULTS: Women with a family history of endometrial cancer had an odds ratio for endometrial cancer of 2.1 (95% confidence interval, 1.1-3.8)). Completion of 1 term pregnancy implied an odds ratio of 0.6 (95% confidence interval, 0.3-1.1). The risk of endometrial cancer decreased significantly with increasing age at first birth and with the number of induced abortions. Use of oral contraceptives for 1 to 5 years decreased the risk of endometrial cancer (odds ratio, 0.2; 95% confidence interval, 0.1-0.3). The odds ratio for endometrial cancer among women who received hormone replacement therapy for 1 to 5 years was 3.1 (95% confidence interval, 1.4-7.0). Body mass index was not demonstrated to be an independent risk factor in this study. The protective impacts of the different exposures (risk factors) can be expressed as etiologic fractions, which indicate how much each exposure reduces the occurrence of endometrial cancer compared with a situation without the existence of that particular exposure. These fractions were as follows: oral contraceptive use for > or =1 year, -45%; 2 term pregnancies, -88%; age > or =30 y when giving birth for the first time, -38%; and a history of incomplete pregnancy, -16%. CONCLUSION: A number of risk factors for endometrial cancer are common to premenopausal and postmenopausal women: family history, reproductive history, hormone replacement therapy, and the use of oral contraceptives. Among young women reproductive variables imply the greatest prophylactic potential.

Abortion, Induced↗
PubMed2002

Effect of early skin-to-skin contact after delivery on duration of breastfeeding: a prospective cohort study.

AIM: To study the influence on breastfeeding of skin-to-skin contact after birth. METHODS: Using a prospective cohort study design, a group of 1250 Polish children was investigated with 3 y follow-up. RESULTS: The implementation of the practice significantly increased mean duration of exclusive breastfeeding by 0.39 mo and overall breastfeeding duration by 1.43 mo. The infants kept with the mothers for at least 20 min were exclusively breastfed for 1.35 mo longer and weaned 2.10 mo later than those who had no skin-to-skin contact after delivery. The skin-to-skin contact after birth significantly coexisted with the other hospital practices supportive to breastfeeding, especially rooming-in without separation longer than 1 h per 24 h [relative risk (RR) = 3.18, 95% confidence interval (95% CI): 2.34-4.31] and first breastfeeding within 2 h after birth (RR = 2.94, 95% CI: 2.36-3.67. Multivariate analysis performed by a general linear model with duration of exclusive breastfeeding as the dependent variable indicated skin-to-skin contact and mother education as two independent variables influencing the duration of exclusive breastfeeding. CONCLUSION: The results indicate that extensive mother-infant skin-to-skin contact lasting for longer than 20 min after birth increases the duration of exclusive breastfeeding.

Adult↗
PubMed1991

Follow-up of spina bifida children with and without upper renal tract changes at birth.

The aim of this study was to assess 2 groups of children with spina bifida; one with and the other without upper renal tract (URT) changes at birth and to evaluate the outcome of their management. In Group 1, there were 148 patients who had normal URT at birth. They were studied for a mean follow-up of 131 months. Twenty-eight per cent developed URT changes in later life. The median time interval for URT changes to develop between birth and the first assessment which showed abnormal finding, was 33 months and between the last normal URT assessment and the development of URT changes, was 16 months. Six patients with URT changes were treated conservatively and 36 required intervention. Twenty-eight of 42 patients showed initial improvement of URT changes but 25 subsequently deteriorated. In 3 patients renal function deteriorated with renal failure in one and renal impairment in 2. In Group 2, 24 patients who had URT changes present at birth were also studied for a mean follow-up of 115 months. The URT changes in 8 patients deteriorated after the initial assessment over a median time of 15 months. Twelve patients' URT changes improved spontaneously without active intervention over a median time interval of 16 months but 5 subsequently deteriorated. Overall, the prognosis of children with URT changes at birth did not seem to be any worse than children developing changes later in life. Lesions of sacral and thoraco-lumbar regions of the spine were most commonly associated with URT changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1998

Fertility problems and breast cancer risk in young women: a case-control study in the United States.

OBJECTIVES: Late age at first birth and nulliparity are established risk factors for breast cancer, yet the extent to which fertility problems contribute to these associations remains largely unexplored. Here, we examine self-reported fertility problems as a risk factor for breast cancer in young women. METHODS: We used a population-based case-control study of 2,173 cases and 1,990 controls aged 20 to 54 years in the United States. Structured in-person interviews were used to elicit detailed information on established and potential breast cancer risk factors. Information was collected on pregnancy details, including difficulties becoming pregnant or maintaining a pregnancy. RESULTS: Self-reported difficulty in becoming pregnant or maintaining a pregnancy was reported by 450 cases and 377 controls. Overall, there was little association between these fertility problems and risk of breast cancer (odds ratio [OR] = 1.05). Parity was associated with a decreased risk of breast cancer in women both with (OR = 0.71) and without (OR = 0.79) fertility problems. There was little evidence of an increased risk of breast cancer with later age at first full-term birth among women without fertility problems (ORage 35+ :age <20 = 1.13, 95 percent confidence interval [CI] = 0.7-1.9), but a relatively strong association among women with fertility problems (ORage 35+ :age <20 = 2.96, CI = 1.3-7.0). Among women with a first full-term birth at age 35 or older, fertility problems were associated with a twofold risk of breast cancer. Analyses of duration of unprotected sexual intercourse prior to first pregnancy as an alternative estimate of infertility produced similar results. CONCLUSIONS: Our study suggests that the association between late age at first birth and breast cancer is stronger among women with self-reported fertility problems than among women with no fertility problems.

Adult↗
PubMed1996

Regularity and length of menstrual cycles in women aged 41-46 in relation to breast cancer risk: results from the DOM-project.

The effect of regularity and length of the menstrual cycle on breast cancer risk was studied prospectively in 78 cases and 383 age-matched controls who participated in a breast cancer screening programme, the DOM-project, in Utrecht, the Netherlands. Before entering the screening programme when they were aged 41-46, the women kept a menstrual calendar during at least three consecutive cycles. Cycles were considered to be irregular if any of three cycles was shorter than 21 days or longer than 35 days and/or if variation between cycle lengths was more than five days. Women with irregular cycles had a significantly reduced risk of breast cancer (odds ratio = 0.44; 95% confidence interval 0.22-0.86) after adjustment for age at menarche, age at first birth, parity, Quetelet's index and family history of breast cancer. Among regularly menstruating women, long cycles (28 days or more) were not significantly associated with increased risk of breast cancer (odds ratio 1.17; 95% confidence interval 0.66-2.09). To the extent that irregular menstrual cycles reflect anovulatory cycles, our findings support the hypothesis that the cumulative number of regular ovulatory cycles increases breast cancer risk.

Adult↗
PubMed2004

Unintended pregnancy among newly married couples in Shanghai.

CONTEXT: Though contraceptive failure and induced abortion in China have both attracted research attention, the somewhat broader topic of unintended pregnancy has been neglected. METHODS: A total of 7,872 newly married couples, enrolled between 1987 and 1988, were followed up until 1994-1995; only 2% were lost to follow-up. During face-to-face interviews, background and fertility-related data were collected. Chi-square tests and logistic regression were used to assess associations with unintended pregnancy. RESULTS: By three months after marriage, 461 couples had conceived; 57% of nonpregnant wives said that their preferred interval between marriage and conception was no more than three months. Twenty-one percent of pregnancies occurring between marriage and first birth were reported as unintended; 81% of these resulted from contraceptive failure. The majority of unintended pregnancies were carried to term; 13% were aborted. The younger the wife and the greater her desired interval between marriage and conception, the greater the likelihood that a pregnancy occurring before first birth was unintended. After first birth, 43% of couples experienced one or more unintended pregnancies, 98% of which were aborted in accordance with the one-child policy. The majority of these pregnancies occurred in the 12 months after first birth, when couples tend to rely on ineffective methods of contraception. The odds of having an unintended pregnancy after first birth were slightly elevated if at least one spouse desired a second child. CONCLUSIONS: Unintended pregnancies are common among married couples in Shanghai. Policies to reduce unintended pregnancies, and abortions, should focus particularly on postpartum contraception.

Adult↗
PubMed1995

Subsequent pregnancy affects morbidity of previous child.

A prospective study of 113 children in rural Bhutan registered their morbidity and weight and their mothers' subsequent pregnancies, monthly for 32 months during the children's first 3 years of life. Children whose mothers had a subsequent birth interval of 18-30 months had an incidence of diarrhoea during the subsequent pregnancy 50% higher than their matched cohort whose mothers did not become pregnant (p = 0.02). The relative risk for diarrhoea calculated from pooled child months was 1.51. Children whose mothers became pregnant also tended to have a higher incidence of skin infections. Children, whose mothers were pregnant when they terminated breastfeeding, experienced an increased incidence of diarrhoea around weaning (p = 0.01). Children weaned at the same age from non-pregnant mothers did not show increased morbidity. This study, for the first time, relates observations of children's morbidity directly in time to the occurrence of the mother's subsequent pregnancy, and provides evidence of a causal relationship between a moderately short subsequent birth interval and a concurrent increase in morbidity for the study child.

Bhutan↗
PubMed1986

Low birth weight in pregnancies following induced abortion: no evidence for an association.

Compared with women delivering a first pregnancy, those delivering a second pregnancy after aborting the first have similar rates of low (less than 2,500 g) birth weight newborns (relative risk (RR) G2A1/G1 = 0.86, 95% confidence interval (CI) = 0.49-1.51) and mean birth weight (delta = 16.3 g, p = 0.63). Abortion of the first pregnancy prevents the reduction in low birth weight and increase in mean birth weight in the second pregnancy which delivery of the first pregnancy normally bestows (RR G2P1/G2A1 = 0.48, 95% CI = 0.25-0.90; delta = 135.3 g, p less than 0.0001). Two prior induced abortions do not significantly increase risk for low birth weight (RR G3A2/G1 = 1.14, 95% CI = 0.37-3.56) or decrease mean birth weight (delta = 29.0 g), compared with women delivering their first pregnancy. The second of two deliveries has a reduced risk of low birth weight irrespective of whether both deliveries follow an aborted first pregnancy. Adjustment for confounding factors did not materially change these results. Low birth weight rates were higher after abortions performed in hospital compared with elsewhere (p = 0.03), but mean birth weight was not affected. Gestation at abortion, vacuum aspiration or dilatation and curettage, and abortion complications were unrelated to birth weight of subsequent pregnancies. Pregnancies conceived within six months of a prior abortion or delivery had lower birth weight than if the antecedent pregnancy ended more than six months previously.

Abortion, Induced↗