The terms preterm and postterm have largely replaced earlier terms of premature and postmature.
Preterm and postterm are defined above, whereas premature and postmature have historical meaning and relate more to the infant's size and state of development rather than to the stage of pregnancy.
Fertilization can also occur by assisted reproductive technology such as artificial insemination and in vitro fertilisation.
Fertilization (conception) is sometimes used as the initiation of pregnancy, with the derived age being termed fertilization age.
After the point of fertilization, the fused product of the female and male gamete is referred to as a zygote or fertilized egg.
The fusion of male and female gametes usually occurs following the act of sexual intercourse.
Common symptoms and discomforts of pregnancy include: In addition, pregnancy may result in pregnancy complication such as deep vein thrombosis or worsening of an intercurrent disease in pregnancy.
The chronology of pregnancy is, unless otherwise specified, generally given as gestational age, where the starting point is the woman's last normal menstrual period (LMP), or the corresponding age of the gestation as estimated by a more accurate method if available.
The sperm and the egg cell, which has been released from one of the female's two ovaries, unite in one of the two fallopian tubes.
Gravidity is a term used to describe the number of times that a female has been pregnant.
Similarly, the term parity is used for the number of times that a female carries a pregnancy to a viable stage.
Sometimes, timing may also use the fertilization age which is the age of the embryo.
Naegele's rule is a standard way of calculating the due date for a pregnancy when assuming a gestational age of 280 days at childbirth.