Having lessons teach you the Japanese you need for pregnancy (like midwife, nausea, Labor, maternity leave etc), babies (breastfeeding, stroller, diaper etc) and small children (playground vocab, kindergarten vocab etc), as well as cultural differences in these aspects. I don’t even know if it’s appropriate to even talk about these topics in Japan, but you never know if it might come in handy when traveling or living there while pregnant or with small children.