Relation of plasma oxytocin and prolactin concentrations to milk production in mothers of preterm infants: influence of stress

Responses of oxytocin and PRL to mechanical breast pumping and the influence of physiological indicators of stress were measured at 2, 4, and 6 weeks postpartum to determine potential causes of inadequate milk production in 18 women with prematurely delivered, nonnursing (<1500 g) infants. Median milk production was similar to that reported in breastfeeding mothers, but a third of mothers were producing less than half as much by week 6. Plasma oxytocin was similar to that previously reported for breastfeeding mothers. The oxytocin area under the curve (AUC) for breast-pumping sessions (70 min) was correlated at each occasion (r = 0.37, 0.58, and 0.55, respectively) with milk yield. Unlike reports of PRL levels in breast-feeding women, PRL AUC declined between weeks 2 and 6 weeks postpartum (P = 0.03); significant increases in plasma PRL occurred in response to pumping at 2 and 4 weeks, but not at 6 weeks. Salivary amylase, a measure of alpha-adrenergic activity, was highly negatively correlated on each occasion with PRL AUC (r = -0.58, -0.68, and -0.86, respectively), but not with oxytocin. Salivary cortisol was negatively correlated to a lesser degree. We hypothesize that deficiencies in preterm lactation are mediated in part upon stress-induced suppression of PRL secretion through an adrenergic mechanism.

Salivary estradiol and progesterone levels in conception and nonconception cycles in women: evaluation of a new assay for salivary estradiol

OBJECTIVE

To determine the usefulness of salivary E2 and progesterone for noninvasive assessment of ovarian function.

DESIGN

Prospective study of salivary hormone levels in women planning a pregnancy.

SETTING

Department of Obstetrics and Gynecology at Northwestern University Medical School in Chicago, Illinois.

PATIENT(S)

Fourteen women aged 23-39 years with regular menstrual cycles who were planning a pregnancy.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Salivary estradiol and progesterone concentrations.

RESULT(S)

The sensitivity of the E2 assay is 2.0 pmol/L; the interassay coefficient of variation was 5.2% (mean value 17 pmol/L). Recovery of E2 added to saliva was 106%. The correlation with simultaneous serum samples was 0.71. Menstrual cycle patterns contained a preovulatory depression and a midcycle surge. By comparison with nonconception cycles, the luteal phases of conception cycles had significantly elevated salivary E2 within the first 5 days after ovulation. Salivary progesterone was significantly elevated but not until 10 days after ovulation.

CONCLUSION(S)

Salivary measurements of E2 and progesterone can be used as noninvasive methods for assessment of ovarian function. Salivary specimens can be collected at home and brought to the laboratory for analysis, obviating the need for frequent phlebotomy. The sensitivity and precision of the salivary E2 assay make it comparable with assays of serum E2 for assessing changes in hormone levels.