Biomedical subjects

L McCowan

Publications and source records attributed to L McCowan.

At least 19 recordsLinked to original sources

PubMed2001

Sleep effects on ambulatory blood pressure measurements in pregnant women.

The aim of this study was to investigate the effect of the definition of daytime and nighttime on ambulatory blood pressure (ABP) in pregnancy. To determine the prevalence of a <10% decrease in mean arterial pressure with sleep (nondipper) in pregnancy and the consistency of nondipper status throughout pregnancy. In a prospective, longitudinal study, 102 pregnant woman underwent 24-h ABP monitoring and recorded sleep patterns at < or = 14, 19 to 22, 27 to 30, 35 to 37 weeks' gestation and 5 to 9 weeks' postpartum. Nighttime was defined by arbitrary hours or actual periods of sleep. Ambulatory blood pressure measurements using the different definitions of nighttime were compared in the total cohort and individual women. Nondipper status of each woman was determined throughout pregnancy and postpartum. At 35 to 37 weeks' gestation, 19% of women napped during the day and 20% were awake during the night. Throughout pregnancy, mean day and night systolic and diastolic ABP measurements were similar whether daytime and nighttime were defined by arbitrary hours or by sleep periods. In individuals, the use of arbitrary hours (day 07:00 to 21:59, night 22:00 to 06:59) compared to sleep periods to define day and night resulted in differences in daytime systolic (SBP) and diastolic blood pressure (DBP) of up to 4 and 5 mm Hg, respectively. Similarly there were individual differences in nighttime SBP up to 10 mm Hg and DBP up to 11 mm Hg. A third of women were nondippers at least once during pregnancy, but only two women were consistent nondippers. The different definitions of day and night did not change group ABP measurements, but resulted in significant variation in ABP measurements in individual pregnant women. Nondippers were common and nondipper status frequently changed during pregnancy.

Adult↗

PubMed2000

Cardiotocography for antepartum fetal assessment.

BACKGROUND: Cardiotocography is a form of fetal assessment which simultaneously records fetal heart rate, fetal movements and uterine contractions to investigate hypoxia. OBJECTIVES: The objective was to assess the effects of antenatal cardiotocography on perinatal morbidity and mortality and maternal morbidity. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register (to 1 November 1998). SELECTION CRITERIA: Randomised trials comparing antenatal cardiotocography with a control group for fetal assessment. DATA COLLECTION AND ANALYSIS: Trial quality was assessed. MAIN RESULTS: Four studies involving 1,588 pregnancies were included. All trials were conducted on high or intermediate risk pregnancies. Antenatal cardiotocography appeared to have no significant effect on perinatal mortality or morbidity. There was a trend to an increase in perinatal deaths in the cardiotocography group (odds ratio 2.85, 95% confidence interval 0.99 to 7.12). There was no increase in the incidence of interventions such as elective caesarean section or induction of labour. The one trial which examined an effect on antenatal patient management showed a significant reduction in hospital admissions and a reduction in inpatient stay in the cardiotocography group. REVIEWER'S CONCLUSIONS: There is not enough evidence to evaluate the use of antenatal cardiotocography for fetal assessment. All of the trials included in this review date from the introduction of antenatal cardiotocography and may be difficult to relate to current practice.

Cardiotocography↗

PubMed2000

Pregnancy outcomes and cardiac complications in women with mechanical, bioprosthetic and homograft valves.

OBJECTIVES: Firstly, to compare pregnancy outcomes and cardiac complications in women with: 1) either mechanical or bioprosthetic valves at the mitral site; 2) mechanical valves treated with warfarin or subcutaneous heparin. Secondly, to determine pregnancy and cardiac outcomes in women with aortic homograft valves. DESIGN: Historical cohort study. SETTING: Greenlane Hospital, Auckland, New Zealand. POPULATION: Young women (n = 255) who had valve replacements between 1972 and 1992. Seventy-nine women underwent 147 pregnancies. MAIN OUTCOME MEASURES: Pregnancy loss, cardiac complications. RESULTS: Pregnancy loss occurred in 59% of pregnancies with mitral mechanical valves (n = 50) and 7% with mitral bioprosthetic valves (n = 33) (RR 8 x 20, 95% CI 2 x 10-31 x 93). Pregnancy loss rate was 70% in pregnancies treated with warfarin, compared with 25% for those switched from warfarin to heparin (RR 2 x 81, 95% CI 1 x 03-7 x 73). All heparin-associated losses occurred in the first trimester, whereas there were four stillbirths with warfarin. Cardiac complications occurred in 10 pregnancies (20%) in the women with mitral mechanical valves and four (13%) with mitral bioprosthetic valves (RR 1 x 55, 95% CI 0 x 53-4 x 52). All four thromboembolic complications with mechanical valves occurred in the 14 women treated with heparin throughout pregnancy. Structural valve deterioration occurred in four pregnancies (10%) with mitral bioprosthetic valves. No cardiac complications or known pregnancy losses occurred with aortic homograft valves (n = 41). CONCLUSION: The high pregnancy loss rate in women with mitral mechanical valves was associated with warfarin throughout pregnancy, whereas the thromboembolic cardiac complications were associated with heparin. Pregnancy outcome was very good in women with bioprosthetic and homograft valves.

Abortion, Spontaneous↗

PubMed2000

The detection, investigation and management of hypertension in pregnancy: executive summary.

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Female↗

PubMed2000

The detection, investigation and management of hypertension in pregnancy: full consensus statement.

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Female↗

PubMed1999

Perinatal predictors of growth at six months in small for gestational age babies.

Poor growth in childhood is associated with a number of later complications and early recognition may enable early intervention to improve outcomes. Approximately 20% of small for gestational age (SGA) babies remain small at two years. Most catch up growth occurs in the first 6 months and smallness at 6 months predicts later small size in the majority of cases. There are no previous reports of perinatal predictors of size at 6 months in SGA babies. The aim of this study was to identify the perinatal factors associated with small size at 6 months in infants who were SGA at birth (birthweight < 10th%). SGA infants had assessments of length, weight, and head circumference performed at three monthly intervals by the same researcher. Detailed perinatal data was collected in all cases. Abnormal size was defined as a length, weight or head circumference measurement < 10th% for 6 months corrected age. Infants were considered to show failure of catch-up growth if measurements at 6 months were further below the population mean than birth measurements. Two hundred and forty eight babies were recruited of whom 203 (82%) completed followup at 6 months. Forty (20%) babies were short, and in logistic regression shortness at 6 months was predicted by shortness at birth and male sex. Thirty one (16%) had weight < 10th% and low weight was predicted in logistic regression by early gestation at diagnosis of SGA (median 30.8 weeks in those who were under weight and 33.9 weeks in those of normal weight p < 0.0001). Thirty seven (18%) had a low head circumference which was predicted by small head size at birth. Three quarters of the babies who were short, underweight, or had low head circumference at 6 months also showed failure of catch-up growth. Shortness and small head circumference at 6 months were predicted by shortness and small head circumference at birth, especially in boys. Underweight was predicted by early detection of SGA antenatally. Most SGA babies who remained small at 6 months failed to show catch up growth after birth.

Adult↗

PubMed1998

Antenatal indomethacin--adverse fetal effects confirmed.

We examined the association between antenatal indomethacin exposure and adverse neonatal outcome in a matched retrospective cohort study of infants born to 72 mothers at less than 31 weeks' gestation. Indomethacin-exposed mothers were matched to controls by gestational age at delivery, antenatal corticosteroid exposure, prolonged spontaneous rupture of membranes, multiple pregnancy, thyrotrophin releasing hormone (TRH) exposure, and neonatal sex. Periventricular haemorrhage was significantly increased for infants delivered within 48 hours of maternal indomethacin exposure (Grade 1 and 2 19% versus 6%, and Grades 3 and 4 28% versus 3% (p<0.03)). Persistent patent ductus arteriosus was more common in those infants delivered within 48 hours of maternal indomethacin exposure (40% versus 20% (p<0.04)). More neonates exposed to antenatal indomethacin failed to respond to postnatal indomethacin to close a patent ductus arteriosus, 60% versus 0% (p<0.04). There were no adverse effects demonstrated of indomethacin administered greater than 48 hours from delivery. We have confirmed a probable association between antenatal indomethacin administration and an increased incidence of neonatal periventricular haemorrhage, patent ductus arteriosus, and impaired renal function. The adverse neonatal effects appear to be greatest when indomethacin is administered within 48 hours of delivery. We recommend that indomethacin should be used with caution as a tocolytic agent for the treatment of preterm labour at gestations less than 31 weeks.

Cerebral Hemorrhage↗

PubMed1997

The levonorgestrel-releasing intrauterine device: a wider role than contraception.

The Levonorgestrel-releasing intrauterine device (LNG IUD) provides excellent contraception; it may reduce the rate of pelvic inflammatory disease (PID) and ectopic pregnancy compared to other 'modern' copper releasing IUDs; it can safely be used in the puerperium for breast-feeding mothers, and it significantly reduces menstrual blood loss and pain. While it was developed primarily as a contraceptive, its potential role in managing heavy and painful menstruation and the symptoms of the climacteric may eventually be just as important. Amongst developed countries New Zealand and Australia have some of the highest hysterectomy rates. By the age of 50 years 1 in 4 women in New Zealand and 1 in 5 women in Australia will have had a hysterectomy (A,B). In New Zealand 90% of these are performed for heavy menstrual bleeding and fibroids (A). The LNG IUD has been shown to be effective treatment for both these conditions and its introduction to New Zealand and Australia would offer women an additional choice beyond surgery.

Contraceptive Agents, Female↗

PubMed1995

Aspirin and prevention of preeclampsia. Position statement of the use of low-dose aspirin in pregnancy by the Australasian Society for the Study of Hypertension in Pregnancy.

1. A heterogeneous group of randomized trials have been conducted using low-dose aspirin to prevent preeclampsia. The results do not support widespread use of low-dose aspirin to prevent preeclampsia. 2. On the basis of existing literature, it is reasonable to use prophylactic low-dose aspirin from early pregnancy in the following groups: (i) Women with prior fetal loss after the first trimester, with placental insufficiency (ii) Women with severe fetal growth retardation in a preceding pregnancy either due to preeclampsia or unexplained (iii) Women with severe early-onset preeclampsia in a previous pregnancy necessitating delivery at or before 32 weeks' gestation. 3. On the basis of existing literature, it is recommended that aspirin not be used in the following groups: (i) Healthy nulliparous women (ii) Women with mild chronic hypertension (iii) Women with established preeclampsia. 4. The data are sufficient to support further trials in more homogeneous select subgroups of women considered at risk of developing preeclampsia.

Aspirin↗

PubMed1993