Pregnancy Glossary

Pregnancy is a complex and wondrous experience. As you progress through your journey to parenthood, you will hear many unfamiliar terms and phrases. Our handy glossary of some of the most common pregnancy-related terms can help ensure that it is not also baffling.

Amniotic fluid: The clear fluid inside the amniotic sac (a bag inside the womb formed of two membranes).  In the early stages of pregnancy it is predominantly composed of water; however, once the baby’s kidneys begin to work, it fills with urine and other fluids from the baby. Amniotic fluid provides a useful cushion to protect baby and also provides an ideal environment for it to begin to experiment with kicking, turning and other in utero movement.

Anomaly scan: Also called the 20 week scan (it usually takes place between 18 and 22 weeks of the pregnancy), the anomaly scan is used to check the development of the baby for any possible abnormalities and also to check the position of the placenta.

Antenatal class: Organised group sessions for parents-to-be providing essential information in the lead up to labour, birth and the first few weeks of caring for a newborn. The classes provide information regarding choices for labour and offer contact with other people in a similar situation.

Assisted birthA birth in which a doctor or midwife uses instruments to help the baby be safely delivered down the birth canal. The most common examples of assisted birth are forceps and ventouse delivery.

Birth plan: A written way for parents to take control and prepare for the birth of their baby. It is also a method for communicating wishes and preferences relating to the birth to all of the clinical and midwifery staff involved in the birth. The plan should be clear, but must also be flexible enough to be suitable for all eventualities occurring on the day.

Blastocyst: The structure of cells formed once the zygote reaches the uterus, following the  repeated division of cells as it travels from the fallopian tube. The blastocyst is typically formed around five days after fertilisation and is made up of an inner cell mass, which will form the embryo, as well as an outer layer of cells (the trophoblast), which will form the placenta. It has a central cavity, known as the blastocoel, which is filled with fluid. The blastocyst will implant itself into the uterine wall, where it will develop into the embryo.

Braxton Hicks contractions: These are effectively “warm up” contractions to help the body prepare for birth. They can feel similar to period pains and may result in temporary tightening of the belly but are not typically painful. It is not entirely clear why they occur, but they may play a role in toning the uterus muscles so they are ready for labour and birth. Braxton Hicks contractions may start very early in the pregnancy but are usually only noticed in the third trimester.

Caesarean section: A caesarean section (also called a C-section), is a type of surgery in which one incision is made into the mother’s abdomen and a second in the uterus so that the baby can be delivered non-vaginally. Caesarean sections are typically made in emergency situations although some women may choose to give birth this way (known as an elective caesarean).

Chorionic villus sampling (CVS): A screening test offered when the chances of a baby being born with a genetic or chromosomal condition is raised. Parents will be offered the test at around the 11th to 14th week of pregnancy. A CVS test can determine if the baby has Down’s, Edward’s, or Patau’s syndrome. Screening requires a sample of chorionic villi cells to be removed from the placenta, usually obtained by inserting a thin needle through the mother’s abdomen. The test is not common and will only be offered if previous screening has indicated there may be a higher chance, or if there is a family history, of chromosomal conditions.

Crown-rump length: Crown-rump length (CRL) is used to measure the length of the embryo or fetus from the top of its head (the crown) to the base of its buttocks (rump) in order to determine its gestational age. CRL is usually measured using ultrasound up to around 19 weeks, at which point, sonographers will take alternative measurements to establish the progression of the pregnancy.

Dating scan: Also known as the ultrasound scan or the 12-week scan. The scan will be offered  from eight to 14 weeks to all expectant mothers by their GP or midwife. Typically carried out at a hospital ultrasound department, the dating scan helps to give a more accurate EDD (estimated date of delivery) and will check how many babies are in the mother’s womb, whether the baby is positioned correctly and that the development is normal

Dry-eye syndrome: Condition common in pregnancy in which reduced hormone levels may cause dry, red, sticky and gritty feeling eyes. In more severe cases the condition may cause pain, severe redness or impaired vision. If necessary dry-eye syndrome will be treated with ointment or drops.

Early labour: Also called “the latent phase”, early labour is the time when the body readies itself for the more demanding phases of later labour.  Generally speaking, it is characterised by painful contractions and the gradual opening of the cervix to around 4cm.

Embryo: An unborn baby in the earliest stage of development. The embryonic stage occurs after the blastocyst has implanted itself into the uterine wall, and is when the baby’s brain and nervous system, limbs, and major organs begin to form. After the eighth week, the embryo is then classified as a fetus.

Epidural: A type of localised anaesthetic used for pain relief during birth, particularly during a Caesarean section. It is injected into the space around the spinal cord and causes loss of sensation in the legs and pelvis – effectively ‘blocking’ the sensation of pain.

Fetus (also foetus): The gestational stage following ’embryo’ commencing at the end of week 8. The fetal period is the last (yet longest) period of development before birth. All the baby’s major organs and features will have formed, and will continue to develop until birth.

Gestational diabetes: High blood sugar which develops during pregnancy. Due to hormonal changes occurring in pregnancy, some women are unable to produce enough insulin, leading to too much glucose in the blood. The condition does not usually cause any symptoms and is diagnosed through a blood test. Gestational diabetes can cause further complications, such as pre-eclampsia and the baby being born with a high birth weight.

Genital herpes: A common infection caused by the herpes simplex virus (HSV), usually transmitted by sexual contact. Although most pregnancies and births having genital herpes as a factor are fine and uncomplicated, it can cause complications, particularly if the mother is experiencing an outbreak for the first time.

Group B streptococcus: A very common type of bacterial infection found in the vagina and/or rectum of around  25% of all women. Most women with the infection have healthy babies. However, in a minority of cases it may be passed to the baby during childbirth. Babies of mothers with the condition are closely monitored and in some cases are given antibiotics following birth.

Haemorrhoids: Enlarged, swollen veins which appear around the rectum and anus. In pregnancy they are caused by hormones relaxing the veins.

Hormones: Numerous chemicals produced by endocrine glands which are released into the bloodstream. They stimulate and regulate activity in cells and organs, helping to control everything from growth to stress and energy. In pregnancy, levels of hormones such as relaxin, oxytocin, oestrogen and progesterone change rapidly and significantly to facilitate and sustain healthy development of the embryo and foetus. These fluctuations of pregnancy hormones are believed to be the main causes of certain symptoms such as morning sickness, tiredness and mood swings.

Hyperemesis gravidarum (HG): A rare condition which causes severe nausea and vomiting.  HG affects one per cent of pregnant women and leads to frequent, prolonged vomiting that is easily triggered, possibly leading to further complications such as weight loss, dehydration, and low blood pressure. The symptoms of HG are typically most severe during the first half of pregnancy, but they may last until birth.

Induction of labour: A clinical method to activate birth. A tablet (pessary) or gel is inserted into the vagina in order to soften and dilate the cervix so that the process of labour can begin. Routinely given to women who have not begun labour by week 42 of the pregnancy.

Lanugo: The fine, downy, unpigmented hair covering the baby’s body from around the fifth month of pregnancy. Although most of the lanugo will have been shed before birth in full-term babies, some hair may remain around the shoulders or in the creases between skin.

Linea nigra: Also called the “pregnancy line”, linea nigra is a dark line that develops in pregnancy and runs down the middle of the belly, from the top of the abdomen to the pelvis. More common among women with darker pigmented skin, linea nigra usually fades soon after pregnancy.

Meconium: A substance made up of what the baby has ingested while in the uterus: lanugo, mucus, amniotic fluid, bile, and water. Meconium is baby’s first poo. Following birth it may be dark green in colour and tar-like in consistency.

Myelin: An insulating and protective covering around nerve fibres essential to the healthy functioning of the nervous system. Begins to form around week 18.

Neural tube: A hollow structure of tissue which develops into the baby’s brain, spinal cord, and nervous system. Defects in the neural cord’s development can lead to congenital abnormalities, including spina bifida and anencephaly.

Obstetric cholestasis: A condition most typically seen in the third trimester of pregnancy in which bile acids accumulate in the bloodstream and cause a persistent and uncomfortable itch. May be associated with an increased risk of complications, although there is no compelling evidence to suggest this.

Ovulation: The release of one or more eggs from the ovaries into the fallopian tube, ready for fertilisation. Typically happens at around the midpoint of the menstrual cycle.

Pelvic floor: A group of muscles supporting control of the bowel and bladder. Found in the groin area, the pelvic floor muscles form a sling-like structure to support the uterus, vagina, bowel and bladder.

Pelvic girdle pain: An umbrella term for all pain experienced in the pelvic region, and sometimes including the abdomen, lumbar spine or thigh. Previously known as symphysis pubis dysfunction.

Placenta A temporary endocrine organ attached to the lining of the womb, formed from the trophoblast, one of the two parts of the blastocyst. It allows oxygen and nutrients to pass from the mother’s bloodstream through to the baby via the umbilical cord. Waste products from the baby also pass through the placenta so that the mother’s system can dispose of them. The placenta acts as a barrier to some harmful substances, but not all, for example alcohol. As an endocrine organ the placenta is responsible for producing a number of essential pregnancy hormones.

Pre-eclampsia: A condition characterised by a dramatic rise in blood pressure, swelling of the face hands and feet and increased protein in the urine. Can lead to kidney or liver problems and may develop into eclampsia, a severe pregnancy complication.

Premature birth: Babies born before week 37 of pregnancy are considered preterm. Not all hospitals have specialist neonatal care units and, if early labour is likely, arrangements will be made for delivery at a hospital which is able to provide the care a premature baby might need.

Pregnancy anaemia: Iron deficiency caused by the body’s demand for extra blood. Pregnancy can also result in B12 or folate anaemia deficiency. All types of pregnancy anaemia should be resolvable using supplements.

Restless legs syndrome: Affects between and 10 and 25 percent of all pregnant women and usually occurs in the third trimester. It is a neurological disorder and is felt as uncomfortable or painful sensations in the legs and a strong desire to move them. Usually most severe at night and typically disappearing four weeks after giving birth. 

Sex drive: Also called “libido”, sex drive describes a person’s appetite for sexual intimacy. Sex drive may be lower in the early weeks of pregnancy but, for some women, may be strong at other stages of the pregnancy, particularly when blood flow is increased to the sexual organs.

Symphysis pubis dysfunction (SPD): An umbrella term for all pain experienced in the pelvic region, and sometimes including the abdomen, lumbar spine or thigh, nowadays usually referred to as pelvic girdle pain.

Uterus Also known as the womb. The uterus is a hollow muscular organ located in the lower body of the woman. It is where the fetus gestates from conception to birth. The fertilised egg will attach to the walls of the uterus, where it will develop into a baby over approximately nine months.

Varicose veins: Enlarged purple or blue veins, most commonly in the legs, affecting around one in three pregnant women. In pregnancy the condition is caused by the placenta and uterus placing extra pressure on the large vein (inferior vena cava). The condition is made worse by the hormone progesterone causing slackening of the vein walls.

Important – If you or your child are unwell you should seek medical advice from a professional – contact your GP or visit an A&E department in an emergency. While My BabyManual strives to provide dependable and trusted information on pregnancy and childcare 24/7 via our website pages, we cannot provide individual answers to specific healthcare questions.