This Article Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by DÍAZ, S. Articles by CROXATTO, H. B. Search for Related Content PubMed PubMed Citation Articles by DÍAZ, S. Articles by CROXATTO, H. B.

Early Difference in the Endocrine Profile of Long and Short Lactational Amenorrhea^*

Laboratorio de Endocrinología P. Uniuersidad Católica de Chile, Facultad Ciencias Biológicas, and Consultorio de Planificación Familiar, Institute Chileno de Medicina Reproductiva Santiago, Chile

Address requests for reprints to: Dr. S. Diaz, Laboratorio de Endocrinología, Facultad Ciencias Biológicas, Casilla 114-D, Santiago, Chile.

The endocrine profiles associated with long and short lactational amenorrhea were assessed in a longitudinal study in which morning blood samples were drawn in 48 women from the first postpartum month until the recovery of ovulation and in a cross-sectional study in which the samples were drawn throughout 24 h at the end of the third postpartum month in 10 fully nursing and amenorrheic women. PRL, LH, FSH, estradiol (E₂), progesterone, cortisol, and dehydroepiandrosterone sulfate were measured.

In both studies we detected a smaller PRL increase in response to suckling (P < 0.001) and higher E₂ levels (P < 0.001) in nursing women who ovulated within 6 months postpartum compared to those in women who did not. Such differences were observed early after delivery when all women were fully nursing and amenorrheic.

These results suggest some probable sources of variability in the duration of lactational amenorrhea in our population. The greater PRL response to suckling associated with longer amenorrhea may be due to higher sensitivity of the breast-hypothalamus-pituitary system or a stronger suckling stimulus in this group. Differences in plasma E₂ levels between longer and shorter periods of amenorrhea may reflect dissimilar endogenous production, intake, or clearence of estrogens.

^* This work was supported by the Special Programme of Research Development and Research Training in Human Reproduction of WHO (Grants 85049 and CHI-LID-86), The Population Council, New York, NY (Grant CB-87.10A/ICCR), and the Rockefeller Foundation.

Received February 12, 1990.

This article has been cited by other articles:

				P. Villaseca, C. Campino, E. Oestreicher, D. Mayerson, M. Seron-Ferre, and E. Arteaga Bilateral oophorectomy in a pregnant woman: hormonal profile from late gestation to post-partum: Case report Hum. Reprod., February 1, 2005; 20(2): 397 - 401. [Abstract] [Full Text] [PDF]

				C. Campino, C. Torres, A. Rioseco, A. Poblete, E. Pugin, V. Valdes, S. Catalan, C. Belmar, and M. Seron-Ferre Plasma prolactin/oestradiol ratio at 38 weeks gestation predicts the duration of lactational amenorrhoea Hum. Reprod., December 1, 2001; 16(12): 2540 - 2545. [Abstract] [Full Text] [PDF]

				A. Perheentupa, H. O. D. Critchley, P. J. Illingworth, and A. S. McNeilly Enhanced Sensitivity to Steroid-Negative Feedback during Breast-Feeding: Low-Dose Estradiol (Transdermal Estradiol Supplementation) Suppresses Gonadotropins and Ovarian Activity Assessed by Inhibin B J. Clin. Endocrinol. Metab., November 1, 2000; 85(11): 4280 - 4286. [Abstract] [Full Text]