caa a22 4500 386396809 CHVBK 20180307112141.0 cr unu---uuuuu 161130e198907 xx s 000 0 eng 10.1017/S0021932000018022 doi S0021932000018022 pii (NATIONALLICENCE)cambridge-10.1017/S0021932000018022 Bønnelykke Birgitte Cytogenetic Laboratory, Aarhus Psychiatric Hospital, Risskov, Denmark Menstrual characteristics of mothers of twins [Elektronische Daten] [Birgitte Bønnelykke] The menarcheal age and frequency of menstrual disorders in mothers of dizygotic (DZ) and monozygotic (MZ) twins born in Denmark in 1984 or 1985 were compared with a control sample of mothers of singleton infants born in the same period. Compared to control mothers, mothers of DZ twins had a lower menarcheal age and a lower frequency of menstrual irregularities—menstrual cycles exceeding 5 weeks duration, varying length of menstrual cycles and episodes of menostasia. Mothers of MZ twins had a higher frequency of intermenstrual bleeding compared to mothers of singletons. All results were adjusted for maternal age and parity. The findings are relevant to the interpretation of aetiological factors leading to twin births and support the hypothesis of differences in sex hormone activity of the mothers of DZ twins in comparison with other women. Copyright © Cambridge University Press 1989 Journal of Biosocial Science Cambridge University Press 21/3(1989-07), 329-334 0021-9320 21:3<329 1989 21 JBS https://doi.org/10.1017/S0021932000018022 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0021932000018022 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Bønnelykke Birgitte Cytogenetic Laboratory, Aarhus Psychiatric Hospital, Risskov, Denmark NATIONALLICENCE 773 0- Journal of Biosocial Science Cambridge University Press 21/3(1989-07), 329-334 0021-9320 21:3<329 1989 21 JBS CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge