Glossary: Terms Starting with "D"

A dating ultrasound is a scan performed early in pregnancy, usually between 8 and 13 weeks, to confirm or establish how far along you are and to calculate your estimated due date (EDD). The sonographer measures the embryo or fetus and compares this to standard growth charts. If the scan date differs from your LMP calculation by more than a few days, the scan result usually takes priority because it is more reliable. A dating scan also checks for a heartbeat, the number of embryos, and the location of the pregnancy in the uterus.

Related: CRL, EDD

A doula is a trained non-medical support person who provides continuous emotional, physical, and informational support before, during, and after birth. During labor a doula might offer breathing reminders, massage, position suggestions, and calm reassurance. Unlike midwives or obstetricians, doulas do not perform medical tasks, but research consistently shows that continuous doula support is linked to shorter labors, lower rates of cesarean section, and greater birth satisfaction. Postpartum doulas can help at home with newborn care, infant feeding, and parental recovery. Hiring a doula is a personal choice that works alongside, not instead of, your medical team.

Related: Birth partner, labor support

DHA, or docosahexaenoic acid, is an omega-3 fatty acid that is essential for the development of your baby's brain, eyes, and nervous system, especially during the third trimester and the first months of life. Your body cannot make enough DHA on its own, so you need to get it from food or supplements. Oily fish such as salmon and sardines are the richest dietary sources, but many pregnant women in Singapore do not eat enough to meet recommendations. Most prenatal vitamins include 200 to 300 mg of DHA, which is the amount supported by international guidelines.

Related: Omega-3, prenatal vitamin

Dilation refers to the opening of the cervix as your body prepares for and progresses through labor. It is measured in centimeters, starting at 0 (fully closed) and reaching 10 centimeters, which signals that your cervix is fully open and you are ready to push. Early labor typically brings dilation from 0 to 6 cm, while active labor takes you from 6 to 10 cm. Your midwife or obstetrician checks dilation through an internal examination. Progress can feel slow at first, but it often speeds up in active labor. Dilation alone does not determine when you will deliver, as effacement and the baby's position also matter.

Related: Cervix, effacement

Delayed cord clamping means waiting at least 60 seconds, and often one to three minutes, after birth before clamping and cutting the umbilical cord. During this time, blood continues to flow from the placenta to your newborn, transferring extra red blood cells and iron. This boost can improve iron stores for the first several months of life, which is particularly important for babies at risk of iron deficiency. The World Health Organization recommends delayed clamping for all healthy births. It is safe for both vaginal and caesarean deliveries unless the baby needs immediate resuscitation or the mother is bleeding heavily.

Related: Umbilical cord, cord blood

Diastasis recti is a separation of the two parallel bands of abdominal muscle (the rectus abdominis) that run down the centre of your belly. As your uterus expands during pregnancy, the connective tissue between these muscles stretches, creating a gap. After birth, this gap may remain, causing a visible ridge or bulge down the midline when you sit up, a feeling of weakness in your core, or lower back pain. Mild cases often improve on their own with guided exercise, but certain movements like sit-ups can make the gap wider if done too soon. A physiotherapist can measure the gap and build a safe recovery plan.

Related: Core rehab, pelvic floor