The genotype of the mother and the fetus influences the efficacy of a teratogen. For example, genotype determines the prevalence of cleft palate in inbred strains of mice whose mothers are administered cortisol during pregnancy.
Most women will not start ovulating in the first six weeks after giving birth.1 Breastfeeding typically delays the onset of ovulation.2 Depending on the intensity of breastfeeding, it can be several months or over a year before you regain your fertility.
Breastfeeding can delay menstruation and ovulation for 20 weeks or more, but it is not uncommon to find your period returning sooner, or much later, than 20 weeks. There are differences among individual women and their hormone levels, so itâs difficult to say when a period will recommence after childbirth.he chance that you will ovulate in the first six weeks post-birth is extremely slight. When you see your obstetrician or midwife for your six week post-birth appointment, itâs a good time to discuss starting contraceptives, if thatâs what you want to do.