Pregnancy Glossary
Understanding pregnancy terminology can help you feel more confident during your prenatal appointments and when reading about your pregnancy. Here are key terms you may encounter.
Amniotic Fluid
The protective liquid contained in the amniotic sac that surrounds and cushions the baby throughout pregnancy. It helps regulate temperature, allows movement, and aids in lung and digestive system development.
Braxton Hicks Contractions
Irregular, usually painless contractions of the uterus that occur throughout pregnancy but are most noticeable in the third trimester. Often called 'practice contractions,' they help prepare the uterus for labor but do not indicate that labor has begun.
Cervix
The lower, narrow end of the uterus that connects to the vagina. During pregnancy, the cervix remains closed and firm to protect the baby. During labor, it dilates (opens) and effaces (thins) to allow the baby to pass through the birth canal.
Conception
The moment when a sperm cell fertilizes an egg cell, typically occurring in the fallopian tube. This usually happens about 14 days after the first day of the last menstrual period in a 28-day cycle.
Dilation
The opening of the cervix during labor, measured in centimeters. Full dilation is 10 centimeters, which means the cervix is open enough for the baby to pass through.
Ectopic Pregnancy
A pregnancy in which the fertilized egg implants outside the uterus, most commonly in a fallopian tube. This is a medical emergency that requires immediate treatment.
EDD (Estimated Due Date)
The predicted date of delivery, typically calculated as 280 days (40 weeks) from the first day of the last menstrual period. Also called EDC (Estimated Date of Confinement). Only about 5% of babies are born on their exact due date.
Effacement
The thinning and shortening of the cervix that occurs during late pregnancy and labor. Effacement is measured as a percentage, from 0% (no thinning) to 100% (fully thinned).
Embryo
The developing baby from the time of conception through the first 8 weeks of pregnancy (10 weeks gestational age). After this period, it is referred to as a fetus.
Fetal Movement (Quickening)
The first movements of the baby felt by the mother, typically between weeks 16-25 of pregnancy. First-time mothers usually feel movement later (around 20-25 weeks) than experienced mothers (around 16-20 weeks).
Fetus
The developing baby from 8 weeks after conception (10 weeks gestational age) until birth. Before this stage, the developing baby is called an embryo.
Full Term
A pregnancy that has reached 39 weeks 0 days through 40 weeks 6 days of gestation. Early term is 37-38 weeks, late term is 41 weeks, and post-term is 42 weeks or later.
Fundal Height
The measurement from the top of the pubic bone to the top of the uterus (fundus), measured in centimeters. After 20 weeks, the fundal height in centimeters roughly corresponds to the number of weeks of pregnancy.
Gestational Age
The age of the pregnancy measured from the first day of the last menstrual period (LMP). This is the standard way pregnancy duration is measured and is about 2 weeks longer than the actual age of the embryo/fetus.
Gestational Diabetes
A type of diabetes that develops during pregnancy in women who did not have diabetes before becoming pregnant. It usually appears in the second or third trimester and is typically screened for between weeks 24-28.
Group B Streptococcus (GBS)
A type of bacteria that can be found in the digestive and reproductive tracts. Pregnant women are typically tested for GBS between weeks 36-37. If positive, antibiotics are given during labor to prevent transmission to the baby.
hCG (Human Chorionic Gonadotropin)
A hormone produced by the placenta after implantation. It is the hormone detected by pregnancy tests. hCG levels typically double every 48-72 hours in early pregnancy.
Implantation
The process by which the fertilized egg (blastocyst) attaches to the lining of the uterus, typically occurring 6-12 days after conception. Some women experience light spotting (implantation bleeding) during this process.
IVF (In Vitro Fertilization)
An assisted reproductive technology where eggs are fertilized with sperm outside the body in a laboratory. The resulting embryos are then transferred to the uterus. Due dates from IVF are typically calculated from the transfer date.
LMP (Last Menstrual Period)
The first day of the most recent menstrual period before becoming pregnant. This date is used as the starting point for calculating gestational age and estimated due date.
Meconium
The first stool passed by a newborn, consisting of materials ingested during pregnancy. It is typically dark green to black and sticky. Passage of meconium before birth can sometimes indicate fetal distress.
Mucus Plug
A thick collection of mucus that seals the cervical canal during pregnancy, providing a barrier against bacteria. It may be expelled in late pregnancy or early labor, sometimes called the 'bloody show' if tinged with blood.
Naegele's Rule
The standard method for calculating the estimated due date. Take the first day of the LMP, add one year, subtract three months, and add seven days. This estimates a 280-day (40-week) pregnancy.
Neural Tube
The embryonic structure that develops into the brain and spinal cord. Neural tube defects (such as spina bifida) occur when this structure does not close properly, usually in the first 28 days after conception. Folic acid supplementation helps prevent these defects.
Ovulation
The release of a mature egg from an ovary, typically occurring around day 14 of a 28-day menstrual cycle. The egg is viable for fertilization for approximately 12-24 hours after release.
Placenta
An organ that develops in the uterus during pregnancy. It provides oxygen and nutrients to the baby, removes waste products, and produces hormones. It is connected to the baby via the umbilical cord.
Placenta Previa
A condition where the placenta partially or completely covers the cervix. It can cause severe bleeding during pregnancy and delivery and may require bed rest or cesarean delivery.
Preeclampsia
A serious pregnancy complication characterized by high blood pressure and protein in the urine, typically developing after 20 weeks of pregnancy. It can affect the liver, kidneys, and brain if untreated.
Prenatal Vitamins
Supplements designed for pregnant women containing essential vitamins and minerals, particularly folic acid (to prevent neural tube defects), iron (to support increased blood volume), and calcium (for bone development).
Preterm (Premature)
A birth that occurs before 37 weeks of gestation. Very preterm is before 32 weeks, and extremely preterm is before 28 weeks. Preterm babies may need specialized medical care.
Trimester
One of three roughly equal periods of pregnancy. First trimester: weeks 1-13; Second trimester: weeks 14-27; Third trimester: weeks 28-40+. Each trimester has distinct developmental milestones.
Ultrasound
An imaging technique that uses sound waves to create pictures of the baby in the uterus. Used to confirm pregnancy, estimate gestational age, check fetal development, and screen for abnormalities.
Umbilical Cord
The cord connecting the baby to the placenta, containing two arteries and one vein. It provides nutrients and oxygen to the baby and removes waste products. It is typically 50-60 cm long at birth.
Vernix
A waxy, white coating that covers and protects the baby's skin in the uterus. It helps with temperature regulation, has antimicrobial properties, and aids in the passage through the birth canal.
Viability
The point at which a fetus could potentially survive outside the uterus with medical support. This is generally considered to be around 24 weeks of gestation, though outcomes vary significantly.