Pregnancy introduces you to a whole new language — words and phrases you might never have heard before, suddenly becoming part of everyday conversation. Whether you’re just starting out or well into your journey, having clear, trustworthy definitions can really help you feel more confident and in control.

Here’s a glossary of some of the most commonly searched pregnancy terms, explained simply.

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Trimesters

Pregnancy is divided into three trimesters, each lasting about three months:

Please note everyone is different!

• First Trimester: Weeks 1–13. This is when your baby’s development starts rapidly, and many early symptoms show up.
• Second Trimester: Weeks 14–27. Often called the “honeymoon phase” because many symptoms ease and the baby grows quickly.
• Third Trimester: Weeks 28 to birth (around week 40). The final stretch where your body prepares for labour.

Physical Changes and Signs

• Morning Sickness: Despite the name, nausea and vomiting can happen any time during the day, especially in early pregnancy. It’s mainly due to hormone changes.
• Linea Nigra: A dark vertical line that may appear on your belly as your skin pigmentation changes.
• Mucus Plug: A thick barrier sealing your cervix during pregnancy, which may come away as labour approaches.
• Braxton Hicks Contractions: These are “practice” contractions your uterus does to get ready for labour — usually irregular and painless.

Labour and Birth Terms

• Waters Breaking: The amniotic sac breaks and fluid is released. This can happen suddenly or gradually, signalling labour is near. In rare cases, the baby is born en caul, meaning still inside the intact amniotic sac — something considered special in many cultures.
• Induction: Sometimes labour needs a little help starting. Induction includes methods like membrane sweeping, medications, or breaking the waters artificially. Since inductions vary and come with pros and cons, it’s important to research and talk with your care provider about what’s best for you.
• Dilation: Your cervix opens from 0 to 10 centimetres to allow the baby through. Note, it doesn’t predict exactly when your baby will arrive.
• Engagement: This means your baby’s head has moved down into your pelvis, getting ready for birth.
• Station: This measures how far your baby’s head has descended in the pelvis, using bony landmarks as points of reference.
• Meconium: The baby’s first bowel movement, which can sometimes be present in the amniotic fluid, needing extra monitoring.

Dates and Measurements

• EDD (Estimated Due Date): Based on your last menstrual period or early ultrasound, this is an estimate. Most babies arrive within two weeks before or after this date.

Other Terms You Might Hear

• Cervical Sweep: A midwife or doctor may gently separate the membranes from your cervix to help start labour. Evidence is mixed, so be sure to ask questions and weigh options.
• Vernix Caseosa: That white, creamy coating you might notice on a newborn’s skin — it protects baby in the womb.
• Colostrum: The nutrient-rich first milk your body makes in late pregnancy and right after birth.
• Skin-to-Skin Contact: Placing your newborn directly on your bare chest immediately after birth, which helps bonding, keeps baby warm, and supports breastfeeding.
• Fourth Trimester: The first 12 weeks after birth, when your body and baby adjust to life outside the womb.
• Nesting: A burst of energy many experience late in pregnancy, driving a strong desire to prepare the home for the new arrival. It’s a common and natural instinct.

A Few More Helpful Terms

• Placenta: The organ that delivers oxygen and nutrients from you to your baby, and removes waste.
• Lightening: When your baby “drops” lower into your pelvis — often relieving pressure on your lungs but increasing pelvic pressure.
• Effacement: The thinning and softening of your cervix in preparation for labour.
• False Labour: Contractions that feel like labour but don’t cause cervical changes.

Pregnancy is full of new experiences, and understanding these terms can help you feel informed and empowered. If anything still feels unclear, don’t hesitate to ask your midwife, doctor, or trusted sources.

Sources

• National Institute for Health and Care Excellence (NICE), Antenatal Care for Uncomplicated Pregnancies, 2021.
• World Health Organization (WHO), Intrapartum Care for a Positive Childbirth Experience, 2018.
• American College of Obstetricians and Gynecologists (ACOG), Practice Bulletin No. 107: Induction of Labor, 2009.
• Mayo Clinic, Pregnancy Week by Week, accessed 2025.

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