Short answers, pulled from the story.
Childbirth typically occurs around 40 weeks from the start of the last menstrual period, a span known as gestational age. This is just over nine months. Counting by fertilization age instead, the length is about 38 weeks.
An embryo is the developing offspring during roughly the first ten weeks of gestational age, when cells differentiate into body systems. After about ten weeks of gestation, which is eight weeks after conception, it becomes a fetus. At that stage the fetus is about 30 mm long and its heartbeat is visible on ultrasound.
Pregnancy is divided into three trimesters of approximately three months each. The first trimester ends around week 12 to 14, the second trimester ends around week 27 to 28, and the third trimester lasts until childbirth. Miscarriage risk is highest during the first trimester.
Minimal consciousness, dreaming, and the ability to feel pain emerge around 30 weeks of gestation. Electrical brain activity is first detected at the end of week 5, but this is primitive neural activity rather than conscious thought, and synapses do not begin to form until week 17.
In 2016, complications of pregnancy resulted in 230,600 maternal deaths, down from 377,000 deaths in 1990. Common causes include bleeding, infections, hypertensive diseases of pregnancy, obstructed labour, and pregnancy with abortive outcome.
Babies born between 39 and 41 weeks of gestation, called full term, have better outcomes than those born before or after. Delivery before 39 weeks raises the risk of complications including underdeveloped lungs, feeding problems, and jaundice, so induction or caesarean before 39 weeks is not recommended unless medically required.
The total fertility rate in 2024 was estimated highest in Niger at 6.64 children per woman and lowest in South Korea at 1.12 children per woman. Pregnancy rates differ by country and region, influenced by cultural, social, and religious norms, access to contraception, and education.