Glossary: Terms Starting with "H"

Human chorionic gonadotropin (hCG) is a hormone produced by the cells that will form the placenta, starting shortly after implantation. It is the hormone that pregnancy tests detect, either in urine or blood. In a healthy early pregnancy, hCG levels typically double every 48 to 72 hours during the first trimester, peaking around weeks 8 to 10 before gradually declining. Doctors sometimes order serial blood hCG tests to monitor whether a very early pregnancy is progressing normally, particularly after fertility treatment or if there is concern about ectopic pregnancy or miscarriage. Home urine tests detect hCG from about 10 to 14 days after ovulation.

Related: Pregnancy test, beta hCG

Head circumference (HC) is an ultrasound measurement of the distance around the outer edge of your baby's skull. It gives doctors a picture of overall brain and skull growth and is one of several measurements used to calculate estimated fetal weight and assess development. HC is plotted on a percentile chart, and results are most meaningful when tracked across multiple scans over time. Measurements that are significantly small may prompt further assessment for conditions affecting brain development, while larger measurements may be a normal family trait or may warrant a follow-up scan. Always discuss results in context with your obstetrician rather than interpreting them in isolation.

Related: BPD, EFW

Hyperemesis gravidarum (HG) is a severe form of pregnancy nausea and vomiting that goes far beyond typical morning sickness. Women with HG may vomit many times a day, be unable to keep food or water down, and lose more than 5% of their pre-pregnancy body weight. This can lead to dehydration, electrolyte imbalances, and nutritional deficiencies that affect both mother and baby. HG often requires hospitalisation for IV fluids, anti-nausea medication, and monitoring. It is more common in first pregnancies, multiple pregnancies, and in women who experienced it in a previous pregnancy. Early treatment leads to better outcomes.

Related: Morning sickness, dehydration

Heartburn in pregnancy is a burning sensation in the chest or throat caused by stomach acid flowing back up into the oesophagus. It becomes more common as pregnancy progresses because the hormone progesterone relaxes the valve between the stomach and oesophagus, and because the growing uterus pushes upward on the stomach. Eating smaller and more frequent meals, avoiding spicy or fried foods, not lying down immediately after eating, and elevating the head of your bed can all bring relief. Certain antacids such as calcium carbonate (Tums) are generally considered safe in pregnancy, but always check with your doctor or pharmacist before taking any medication.

Related: Reflux, indigestion

Hemorrhoids are swollen, enlarged veins in or around the rectum and anus. They are very common during pregnancy and after birth because increased blood volume and the growing uterus put extra pressure on the pelvic veins, and straining from constipation makes them worse. They can cause itching, discomfort, or bright red bleeding after passing stools. Most improve on their own within a few weeks after delivery. To manage them, prevent constipation with fiber and fluids, use witch hazel pads or an ice pack for relief, and avoid sitting on the toilet for long periods. Over-the-counter creams safe for pregnancy are available at most Singapore pharmacies.

Related: Constipation, pelvic pressure

The heel prick test is a simple procedure performed in the first 48 to 72 hours after birth, where a small drop of blood is collected from your newborn's heel using a tiny lancet. The blood is absorbed onto a special card and sent to a laboratory to screen for metabolic and genetic conditions such as congenital hypothyroidism, phenylketonuria, and other disorders that can cause serious problems if left untreated. The discomfort is brief, and your baby may cry for a moment. Feeding your baby just before the test and holding them skin-to-skin during the procedure can help them stay calm.

Related: Newborn screening

A hearing screen is a quick, painless test done in the first day or two after birth to check whether your newborn can hear properly. Tiny earphones or sensors are placed near your baby's ears while they sleep, measuring how the inner ear or brain responds to sound. Catching hearing loss early is important because speech and language development begins from birth. Babies who are identified and supported before six months old have much better long-term communication outcomes than those identified later. The test is non-invasive and takes only a few minutes.

Related: Newborn screening