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Biomedical subjects

P W Howie

Publications and source records attributed to P W Howie.

At least 73 records · Page 4Linked to original sources
PubMed1983

Fertility after childbirth: pregnancy associated with breast feeding.

During studies on the resumption of fertility postpartum in 12 breast feeding mothers who were using no contraception, eight pregnancies occurred. In seven cases these pregnancies occurred while the mothers continued to breast feed while in one it occurred within 2 weeks of weaning. In two cases pregnancy occurred prior to first postpartum menstruation but followed an abrupt decline in suckling frequency and duration resulting in resumption of follicular development and ovulation. In the remaining six cases, pregnancy was preceded by between 1 and 7 menstrual cycles, the majority of which (13/19) had deficient luteal phases or were anovular (4/19). In all mothers a significant decrease in the suckling frequency and duration observed during lactational amenorrhoea had occurred prior to the resumption of ovulation and conception. No mother conceived with a suckling frequency of greater than three times per day although some mothers ovulated without conceiving when suckling four times per day. The results suggests that if a breast feeding mother wishes to rely upon the infertility associated with lactational amenorrhoea, she must suckle at least five times per day with a total suckling duration of more than 65 min per day (more than 10 min per feed). Any reduction below either of these limits may result in a return of fertility.

Adult↗
PubMed1982

Fertility after childbirth: infant feeding patterns, basal PRL levels and post-partum ovulation.

The infant feeding patterns at the time of first ovulation after childbirth were determined in a longitudinal study of twenty-seven mothers who chose to breast feed their babies. Fourteen mothers suppressed ovulation throughout lactation and thirteen ovulated while still breast feeding. Those who ovulated while breast feeding had all introduced two or more supplementary feeds/day, reduced suckling frequency to less than six times/day and reduced suckling duration to less than 60 min/day at the time of first ovulation. Basal PRL levels had fallen to below 600 microunits/l in all but one of the mothers at first ovulation. Those mothers who suppressed ovulation for more than 40 weeks post-partum (late ovulation group) were compared with those who ovulated between 30 and 40 weeks post-partum (middle group) and with those who ovulated before 30 weeks post-partum (early group). The late ovulation group breast-fed for longest, suckled most intensively, maintained night feeds for longest and introduced supplementary feeds most gradually. This study suggests suckling may be the most important factor inhibiting the return of ovulation during lactation and that policies which encourage increased suckling frequency and duration will maximize the contraceptive effects of breast feeding.

Adult↗
PubMed1982

Fertility after childbirth: adequacy of post-partum luteal phases.

Normal ranges of urinary pregnanediol and total urinary oestrogen were determined from weekly estimations in twenty-seven cycles from seven normally menstruating control women and compared with the levels in the cycles of twenty-seven breast feeding and ten bottle feeding mothers. During lactation, the luteal phase pregnanediol levels were within normal limits in thirteen of forty-nine (27%) cycles, the remainder of the luteal phases being deficient (31%) or absent (42%). The proportion of normal luteal phases remained low during first cycles after lactation in six of twenty-three (26%) but rose to twenty-four of thirty-one (77%) in subsequent cycles. In bottle feeding mothers, the luteal phases of first post-partum cycles were deficient in two of ten (20%) and absent in eight of ten (80%). In second post-partum cycles, the majority of luteal phases were deficient (eight of ten, 80%) and it was not until third post-partum cycles that seven of eight (88%) had luteal phase pregnanediol levels in the normal range. Cycles during lactation and first cycles after lactation had significantly lower mean urinary pregnanediol and total urinary oestrogen levels than both the control cycles and the later cycles after lactation. Similarly, first post-partum cycles in bottle feeders had lower urinary pregnanediol and total urinary oestrogen levels than controls. This study shows an increased frequency of abnormal luteal phases during the early post-partum menstrual cycles of both breast and bottle feeding mothers which may be associated with defective development of the follicle.

Adult↗
PubMed1981

Effect of supplementary food on suckling patterns and ovarian activity during lactation.

Patterns of infant feeding, basal prolactin concentrations, and ovarian activity were studied longitudinally in 27 breast-feeding mothers from delivery until first ovulation. Suckling frequency (6.1 feeds/day) and suckling duration (122 mins/day) reached peak values four weeks post partum and remained relatively constant until the introduction of supplementary food at a mean of 16 weeks post partum. There were subsequently sharp declines in both the frequency and duration of suckling, both of which correlated closely with basal prolactin concentrations. None of the 27 mothers ovulated during unsupplemented breast-feeding, but within 16 weeks of introducing supplements ovarian follicular development had returned in 20 and ovulation in 14 mothers. The mothers who ovulated within 16 weeks of giving supplements had reduced frequency and duration of suckling more quickly and weaned more abruptly than those who continued to suppress ovulation. These data suggest that the introduction of supplementary food may exert an important and hitherto unrecognised effect on the timing of first ovulation by reducing the frequency and duration of suckling episodes.

Adult↗
PubMed1981

How long should a breast feed last?

Patterns of milk flow were studied in 50 mothers who were breast-feeding normal birth-weight babies on days 5-7 of the puerperium by progressive test weighing at 5-min intervals during two consecutive feeds. Compared with a regime in which mothers attempted to feed for 10 X 10 min on alternate breasts, a regime of 5 X 5 X 5 X 5 min increased the amount of milk taken in the first 10 min did not influence the final milk intake of the suckling-induced prolactin release. The wide variation of breast-feeding patterns between mothers was demonstrated in respect of the duration of the feed (mean 17.3 min; S.D. +/- 3.1; range 7-30 min), the initial rate of milk flow (mean 6 g/min; S.D. +/- 4.2, range 1-14 g/min) and the final milk intake (mean 70.9 g; S.D. +/- 20.5, range 42-125 g). The advice to breast-feed for 20 min was in appropriate for the majority of mothers because the nutritive feeding time was 15 min or less in 75% of the feeding episodes. The milk intake correlated with the initial rate of milk flow but not with the duration of the feed, the infant's birth weight, or the time since the last feed. It is suggested that the duration of a breast feed should be determined by the infant's response and not by an arbitrary time schedule.

Body Weight↗
PubMed1981

The indicence of severe pre-eclampsia amongst mothers and mothers-in-law of pre-eclamptics and controls.

In order to distinguish between a maternal, fetal or maternal and fetal genetic predisposition towards severe pre-eclampsia, the first pregnancies of 158 mothers and 160 mothers-in-law of pre-eclamptic women and of matched controls were analysed. Fourteen per cent of mothers of pre-eclamptics were found to have had severe pre-eclampsia, confirming previous suggestions that the condition "runs in families', in contrast to only a 3% incidence amongst mothers of controls. The incidence in mothers-in-law of both pre-eclamptics and controls was 4%, in full agreement with a maternal genotype hypothesis and suggesting that the fetal genotype plays, at most, only a minor role in the aetiology of severe pre-eclampsia. The data are in agreement with the hypothesis that a single recessive gene acting in the mother could be responsible for severe pre-eclampsia, but multifactorial inheritance is not ruled out. Mild pre-eclampsia showed no such familial tendency, indicating that the mild and severe forms of pre-eclampsia may represent separate pathological entities.

Female↗
PubMed1980

Factor VIII related antigen/coagulant activity ratio as a predictor of fetal growth retardation: a comparison with hormone and uric acid measurements.

Factor VIII related antigen (VIIIRAg), Factor VIII coagulant activity (VIIIC), plasma uric acid, total plasma oestriol, plasma human placental lactogen (hPL) and urine oestrogen/creatinine ratio were measured in a group of 21 patients clinically suspected of fetal growth retardation and compared with normal pregnancy. Of the hormone assays, hPL was better than either oestrial or oestrogen/creatinine ratio at distinguishing between normal and growth retarded pregnancies. Uric acid levels tended to be higher than normal in patients with fetal growth retardation, but the best means of distinguishing normal from growth retarded pregnancies proved to be the VIIIRAg/VIIIC ratio. This ratio was significantly elevated in fetal growth retardation compared with normal pregnancy, and the increase was evident as early as 30 weeks gestation. Using the VIIIRAg/VIIIC ratio test, the outcome of 17 of the 21 suspect pregnancies could be correctly predicted.

Antigens↗
PubMed1980

The relationship between suckling-induced prolactin response and lactogenesis.

The PRL response to suckling was studied during the first week of the puerperium. Mean basal levels of PRL showed no significant changing during the first week of the puerperium, but there were progressive rises in both the maximum suckling-induced response and the total area under the response curve, which reached peak values on the fourth day after delivery. Despite large variations between individuals in basal PRL levels (range, 0.3-7.0 U/liter), peak suckling-induced response (range, 0.1-9.9 U/liter), and total response (range, 0.6-63.0 arbitrary units), there was much less variability within individuals between consecutive feeds. Using an electronic balance, 20 patients on days 5 and 6 were classified either as good feeders (greater than 60 g milk/feed) or poor feeders (less than or equal to 60 g milk/feed) on the basis of 2 consecutive test weights. The mean PRL response to suckling in 11 good feeders was no different from that in 9 poor feeders, and there was no significant correlation between milk yield and PRL response. Six patients whose infants were in the special care nursery had lactation initiated and maintained by breast pump for an average of 5.6 days. Although the PRL response to the breast pump was very small, these patients also had satisfactory milk yields (mean, 86 g). Although the presence of PRL is essential for lactation, the data in this paper suggest that there is no close temporal correlation between PRL concentrations and milk yield.

Body Weight↗