Pregnancy starts on the first day of the last menstrual period before conception. (Image credit: JGI/Jamie Grill via Getty images) Share this article 0 Join the conversation Add us as a preferred source on Google Newsletter Subscribe to our newsletter As placental mammals, humans give birth to live young. Pregnancy begins on the first day of the last menstrual period, roughly two weeks before conception.
A human pregnancy consists of three trimesters and generally lasts around nine months. But how much do you know about how babies develop? For example, did you know some cell types appear only during pregnancy, or that hair usually grows thicker and lusher during pregnancy due to hormones, but that this extra hair falls out months later after giving birth?
More science quizzes
- Human evolution quiz: What do you know about Homo sapiens?
- Human skeleton quiz: What do you know about the bones in your body?
- Heart quiz: What do you know about the body's hardest-working muscle?
Sophie BerdugoStaff writerSophie is a U.K.-based staff writer at Live Science. She covers a wide range of topics, having previously reported on research spanning from bonobo communication to the first water in the universe. Her work has also appeared in outlets including New Scientist, The Observer and BBC Wildlife, and she was shortlisted for the Association of British Science Writers' 2025 "Newcomer of the Year" award for her freelance work at New Scientist. Before becoming a science journalist, she completed a doctorate in evolutionary anthropology from the University of Oxford, where she spent four years looking at why some chimps are better at using tools than others.
View MoreYou must confirm your public display name before commenting
Please logout and then login again, you will then be prompted to enter your display name.
Logout
