Glossary: Terms Starting with "M"

A midwife is a trained healthcare professional who provides care throughout pregnancy, labor, birth, and the weeks after delivery. Midwives monitor fetal growth, run antenatal checks, support you through contractions, assist with the birth, and help with breastfeeding and newborn care afterward. They are skilled at identifying complications and referring you to an obstetrician when needed. In Singapore, midwives work alongside obstetricians in hospitals like KKH and NUH rather than as independent homebirth practitioners. Their hands-on presence during labor is often one of the most reassuring parts of the birth experience for new parents.

Related: Birth center, home birth

Maternal-fetal medicine (MFM), also called perinatology, is a medical subspecialty focused on pregnancies that carry higher risks for the mother, baby, or both. MFM specialists manage conditions such as preeclampsia, gestational diabetes, twins or higher-order multiples, fetal abnormalities, and pregnancies complicated by heart disease, lupus, or other chronic illnesses. They perform detailed fetal anatomy scans, amniocentesis, and fetal procedures when needed. Your regular obstetrician may refer you to an MFM specialist for a single consultation or for ongoing co-management throughout your pregnancy. The goal is to optimise outcomes for both you and your baby.

Related: Perinatologist, high-risk pregnancy

Morning sickness refers to nausea and vomiting during pregnancy, most common in the first trimester but often occurring at any time of day or night despite the name. It affects up to 80% of pregnant women and is thought to be triggered by rising levels of the pregnancy hormone hCG. For most women, symptoms peak around weeks 8 to 10 and ease by week 14 to 16. Staying hydrated, eating small frequent meals, avoiding strong smells, and trying plain crackers before getting out of bed can help. Rest when you can and do not skip meals, as an empty stomach often makes nausea worse.

Related: Nausea, hyperemesis

The mucus plug is a thick, jelly-like collection of mucus that forms inside the cervix early in pregnancy. It acts as a protective seal, blocking bacteria and infections from reaching the uterus and baby. As labour approaches, the cervix begins to soften and open, and the plug is gradually dislodged. It may come out as a single lump, in small pieces over several days, or go unnoticed entirely. It can be clear, pinkish, or slightly streaked with blood. Losing the mucus plug is a sign that your body is preparing for labour, though active labour may still be days or weeks away.

Related: Bloody show, cervix

A membrane sweep, also called a stretch and sweep, is a procedure where your midwife or doctor inserts a finger into the cervix and makes a circular sweeping motion to separate the amniotic membranes from the lower part of the uterus. This releases prostaglandins, natural hormones that can encourage the cervix to ripen and labor to begin. It is usually offered from around 38 to 40 weeks of pregnancy for low-risk women who are approaching or past their due date. The procedure is quick and done in a clinic or hospital room without any medication, though it can feel uncomfortable and may cause some cramping or light spotting afterward.

Related: Induction, cervix

Milk coming in refers to the transition from colostrum to mature breast milk, usually happening between day 2 and day 5 after birth. During this time your breasts may feel noticeably fuller, heavier, and warmer as milk volume increases significantly. Colostrum, the early thick yellow milk, has been feeding your baby since birth, so this shift does not mean your baby was going without. Feeding your baby frequently in the first days helps trigger this process. If your milk seems delayed beyond day 5, speak with a lactation consultant to check latch, feeding frequency, and any underlying factors.

Related: Colostrum, engorgement

Mastitis is inflammation of breast tissue that causes pain, redness, swelling, and warmth in one breast, often alongside flu-like symptoms such as fever, chills, and body aches. It is most common in the first few weeks of breastfeeding and can develop from blocked milk ducts or bacteria entering through cracked nipples. Continuing to breastfeed or pump from the affected breast is important because stopping can worsen the condition. Rest, plenty of fluids, and pain relief such as paracetamol help manage symptoms. If symptoms do not improve within 12 to 24 hours, a doctor may prescribe antibiotics that are safe to take while breastfeeding.

Related: Engorgement, clogged duct

Meconium is your newborn's first bowel movement, typically passed within 24 to 48 hours after birth. It is dark greenish-black, thick, and sticky, made up of materials your baby swallowed in the womb, including amniotic fluid, mucus, bile, and skin cells. Unlike regular baby poo, it has almost no smell. Passing meconium is an important sign that your baby's digestive system is working properly. If your baby has not passed meconium within 48 hours, your care team will investigate to rule out conditions like Hirschsprung's disease or intestinal blockage.

Related: Newborn stool, meconium-stained fluid

Meconium-stained amniotic fluid occurs when a baby passes meconium before or during labour, turning the usually clear fluid greenish or yellowish. This happens in around 10 to 15 percent of births and is more common in pregnancies that go past 40 weeks. Meconium in the fluid can be a sign of foetal stress. The main concern is meconium aspiration syndrome, where the baby inhales the fluid into the lungs at birth, causing breathing difficulties. The care team will assess the colour and consistency of the fluid and closely monitor the baby during labour and immediately after delivery.

Related: Meconium, fetal monitoring

Macrosomia means a baby is born with a very high birth weight, most commonly defined as 4,000 grams (4 kg) or above, though some guidelines use 4,500 grams as the threshold. It differs from large for gestational age because macrosomia uses an absolute weight cutoff rather than a percentile comparison. Common causes include gestational diabetes, maternal obesity, prolonged pregnancy, and genetics. During delivery, macrosomic babies have a higher risk of shoulder dystocia, birth injuries, and assisted delivery. After birth, these newborns should be monitored for hypoglycaemia, as their blood sugar can drop quickly once the cord is cut.

Related: LGA, shoulder dystocia