Maternal, prenatal and perinatal characteristics and first trimester maternal serum hormone concentrations

Abstract

In uncomplicated pregnancies, first trimester androgen, oestrogen and prolactin concentrations were higher in nulliparous (n ¼ 160) than parous (n ¼ 260) mothers. Androgens and estrogens were higher in younger than older mothers. These data are consistent with elevated hormone concentrations mediating the breast cancer protection from a first pregnancy and pregnancies occurring at younger ages. There are few opportunities to directly evaluate the hypothesis that the pregnancy hormonal milieu influences cancer risk in the mother and offspring. Investigations have instead used proxies to reflect the endocrine environment such as birth weight which is associated with a modestly elevated breast cancer risk in the daughter (Michels and Xue, 2006). Whereas age at first and last pregnancy and parity are established maternal breast cancer risk factors (National Cancer Institute, 2003), associations have been less consistent for other pregnancy characteristics with regard to the mother (Cnattingius et al, 2005) and offspring (Potischman et al, 2004).The few studies on hormone variations by maternal and pregnancy characteristics have focused on maternal measures in mid-or late pregnancy, primarily estrogens. Because the timing of carcinogenic events is unknown, characterising hormones over the entire pregnancy may provide additional insights into the biological mechanisms for maternal and perinatal breast cancer risk factors. MATERIALS AND METHODSData derived from an obstetrical study at the Massachusetts General Hospital (MGH) in Boston, Massachusetts that began in 1998 (Thadhani et al, 2001). Women were recruited at their first prenatal visit (ranging from 6.4 to 19.9 weeks gestation (median 11) with over 90% in the first 13 weeks), interviewed, and asked to provide a blood sample. Participants gave informed consent and the study was approved by the MGH Institutional Review Board. The study sample, described previously (Potischman et al, 2005), includes 109 Hispanic, 56 African American and 255Caucasian women 18 -42 years of age (median 29.6), who delivered a live, singleton birth in an uncomplicated pregnancy. A total of 38% of the women were nulliparous. Laboratory assaysSample handling, storage and assays were described previously (Potischman et al, 2005). Intra-class correlation coefficients from repeated measures of blind quality control samples were 97% for oestradiol, 92% for SHBG, 90% for oestrone, 85% for androstenedione, 76% for prolactin, 76% for testosterone, 60% for progesterone and o50% for DHEAS. Hormone medians and ranges have been published (Potischman et al, 2005). Statistical methodsSpearman correlation coefficients were calculated using continuous data. All pregnancy factors associated with the hormones in unadjusted analyses were entered with gestational age at blood collection (excluding pregnancies with 14 þ weeks' gestation) into linear regression models with logarithm-transformed hormones as dependent variables. Exponentiated b estimates (À1.0) from these models are presented for factors which r...

Determinants of Maternal Sex Steroids During the First Half of Pregnancy

“…The observed decrease in androgen concentrations with maternal age is in line with previous findings during the three trimesters of pregnancy (10, 18, 19). It is unlikely that the reduction is pregnancy-specific as androgen concentrations decrease with age also in non-pregnant women (20).…”

“…Because most studies have investigated the correlates of maternal hormones during mid- or late pregnancy, comparatively little is known about their determinants during the first half of pregnancy (10). Early pregnancy is especially important to the fetus because this is the period when organogenesis takes place.…”

Perfluoroalkyl substances and ovarian hormone concentrations in naturally cycling women

“…For this reason, the possibility of reverse causality has complicated attempts to determine whether PFAS may interfere with fecundity, as marked by time to pregnancy (31, 35, 36, 93, 94). In the current study, parity was a potential confounder given that many PFASs are lower in parous women (92) and ovarian hormones may be as well (95-97). At the same time, because concentrations of PFASs are so dependent on parity and breast-feeding history, the relationship between PFASs and ovarian hormones may differ in parous and nulliparous women, with the latter providing a “cleaner” population in which to study the possible effects of PFASs on the ovary.…”

Birth weight and other prenatal factors and risk of breast cancer in Asian-Americans

“…Although higher intrauterine exposure to endogenous estrogens in older mothers has been hypothesized to explain the elevated risk associated with maternal age and breast cancer risk in daughters, the association between maternal age at pregnancy and estrogen levels is not consistent. Estradiol concentrations were lower in older mothers in some studies [43, 44] but not in other studies [45, 46]. These studies included women with different pregnancy history (first vs multiple previous pregnancies) and the hormone levels were measured during different trimesters of the pregnancy.…”