Lactational amenorrhea/anovulation and some of their determinants: a comparison of well-nourished and undernourished women.

OBJECTIVE

To study the effect of maternal nutritional status and some other possible determinants on lactational amenorrhea/anovulation.

DESIGN

Prospective matched-pairs study.

SETTING

Postpartum wards and community and academic settings.

PATIENT(S): Thirty matched pairs of otherwise healthy, well-nourished (body mass index > or = 26.00 kg/m2) and undernourished (body mass index < or = 19.00 kg/m2) postpartum women were selected.

INTERVENTION(S): Infant feeding pattern was recorded weekly, and infant weights, maternal body mass index, and maternal PRL levels were estimated every 4 weeks until resumption of menstruation. Ovulatory activity was determined using urinary estrone and pregnanediol glucuronide concentrations.

MAIN OUTCOME MEASURE(S): Time of resumption of menstruation, regular and ovulatory.

RESULT(S): Well-nourished women resumed regular menstruation significantly earlier than undernourished women but resumed ovulatory menstruation at almost the same time. Undernourished women had fewer anovulatory cycles preceding first postpartum ovulation and a higher prevalence of formula feeding. Effect of body mass index on lactational amenorrhea became nonsignificant when nonintroduction of formula feeds, maternal age, and socioeconomic status were controlled for.

CONCLUSION(S): Improved maternal nutritional status has no significant effect on fertility: ovulation is not advanced despite early resumption of regular menstruation.