Pregnancy is typically divided into three trimesters.The first trimester is from week one through 12 and includes conception. The fertilized egg then travels down the fallopian tube and attaches to the inside of the uterus, where it begins to form the fetus and placenta. Around the middle of the second trimester, movement of the fetus may be felt.
Term pregnancy is 37 to 41 weeks, with early term being 37 and 38 weeks, full term 39 and 40 weeks, and late term 41 weeks. Babies born before 37 weeks are preterm and are at higher risk of health problems such as cerebral palsy.
About 213 million pregnancies occurred in 2012, of which, 190 million were in the developing world and 23 million were in the developed world.
The number of pregnancies in women ages 15 to 44 is 133 per 1,000 women.
In 2013, complications of pregnancy resulted in 293,000 deaths, down from 377,000 deaths in 1990.
Common causes include maternal bleeding, complications of abortion, high blood pressure of pregnancy, maternal sepsis, and obstructed labor.
Similarly, the term parity (abbreviated as "para") is used for the number of times a female carries a pregnancy past 20 weeks of gestation.
Twins and other multiple births are counted as one pregnancy and birth.
A woman who has never been pregnant is referred to as a nulligravida.
A woman who is (or has been only) pregnant for the first time is referred to as a primigravida, Therefore, during a second pregnancy a woman would be described as gravida 2, para 1 and upon live delivery as gravida 2, para 2.