Prevalence of polycystic ovary syndrome in women from opposite-sex twin pairs.
BACKGROUND
Intrauterine androgens of a male fetus may influence the female fetus in opposite-sex twin pairs. Because female intrauterine overexposure to androgens could lead to polycystic ovary syndrome (PCOS), the prevalence of PCOS should be higher in women from opposite-sex twin pairs. Therefore, the aim of the current study was to evaluate the prevalence of PCOS in women from opposite-sex twin pairs compared to women from same-sex twin pairs, sisters, and female spouses of twins.


METHODS
Data from 1325 monozygotic twins, 1191 dizygotic twins (711 women from same-sex twin pairs and 480 women from opposite-sex twin pairs), 745 sisters of twins, and 218 spouses of male twins were evaluated. PCOS was defined as less than nine natural menstrual cycles a year combined with either hirsutism or acne. The prevalence of PCOS was compared using a chi2 test. Binary logistic regression analyses were conducted to test for confounding effects of smoking, age, and body mass index.


RESULTS
No significant differences in PCOS prevalence were found between women from same-sex twin pairs (either monozygotic or dizygotic), opposite-sex twin pairs, sisters, and spouses.


CONCLUSIONS
The prevalence of PCOS is not different in women from opposite-sex and same-sex twin pairs, singleton sisters, or spouses. This indicates that possible androgen exposure of the female fetus, caused by a shared intrauterine environment with a male fetus, does not result in PCOS-like traits.
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, VU University Medical Center, Amsterdam 1007 MB, The Netherlands.
Esther A M
EA
Kuijper
Jacqueline M
JM
Vink
Cornelis B
CB
Lambalk
Dorret I
DI
Boomsma
D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D004200:Diseases in Twins / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011085:Polycystic Ovary Syndrome / Q000453:epidemiology* / Q000209:etiology; D015995:Prevalence; D012907:Smoking / Q000453:epidemiology; D014429:Twins, Dizygotic; D055815:Young Adult