Week 27: Closing the Second Trimester

The last week of the second trimester sits at week 27. The third trimester opens at week 28, the calendar gets short, and the symptoms that have eased in the second trimester start to come back in heavier forms. Most weekly updates frame this as a kind of border crossing — Saturday you are pregnant-in-the-good-middle-trimester, Sunday you are pregnant-in-the-final-third. It does not feel that way from the inside. The transition is gradual, and the trimester boundaries are clinical conveniences as much as physiological ones. Still, this is the last week of the chapter that began with the anatomy scan and the first kicks and the long stretch where you mostly felt like yourself.

The baby is now 13¾ inches long and weighs 2¼ pounds, the length of a head of cauliflower, the weight of a large eggplant. Most of the developmental architecture is in place. The work from here is finishing.

This week

The headline event of week 27 is the eyes. Cleveland Clinic reports that this is the week "the fetus can open its eyes and blink. It also has eyelashes." The APA echoes this, the eyelids, fused since week 11, are now functional and the baby spends part of each day with them open. Vision is rudimentary in the dark of the uterus, but the bright orange glow that comes through your abdomen on a sunny day reaches them. There is reasonable evidence that fetuses turn toward light at this stage.

The second milestone is rhythm. The APA notes that the baby "has also developed a regular wake and sleep cycle" by now, twenty-minute naps for newborns are foreshadowed here, in a body the size of a cauliflower, sleeping and waking on a roughly forty-minute pattern. Some of what you read as kick patterns is in fact a small person waking up and going back to sleep on a schedule you cannot see.

The third milestone, charming and undignified, is hiccups. The APA puts the new behavior plainly: "it is likely that your baby has hiccups. This is completely normal and may occur quite frequently during this last part of your pregnancy." Fetal hiccups feel like rhythmic, evenly spaced taps from the inside, once a second, usually for a few minutes at a stretch, sometimes for fifteen or twenty. They are believed to be diaphragm practice and are entirely harmless.

The brain is also in one of its most intense growth phases. The cortex is folding, the wrinkled topography of a mature brain begins forming this week, replacing the smooth surface of an earlier embryonic brain. Brain weight roughly triples between now and full term.

What's happening in your body

Your fundal height should be around 27 centimeters, within the two-centimeter band Cleveland Clinic flags as normal. Your provider may finally have committed to bi-weekly visits, the standard escalation through pregnancy is monthly until 28 weeks, bi-weekly from 28 to 36, weekly from 36 onward. Some providers begin the bi-weekly schedule at 27.

The most common new symptom this week is sleep disruption. Three pressures combine to make rest hard. The diaphragm is compressed, so deep breaths feel harder. The bladder is compressed, so bathroom trips multiply. The lower back is tired by 7pm. Side-sleeping with a pillow between the knees is the standard recommendation. A second pillow under the belly for support helps if you can sleep on your left side, which is the recommended position for optimal blood flow to the placenta.

Leg cramps, the kind that wake you from sleep with a calf seizing — are common this week. The likely cause is mineral balance. Magnesium and calcium both help; bananas, leafy greens, and dairy are the food sources usually recommended. Stretching the calf hard against a wall before bed reduces frequency for most people.

Braxton-Hicks contractions, the irregular practice contractions of the uterus, may make their first appearance this week if they haven't already. They feel like a hard, brief tightening of the entire belly — usually painless, usually irregular, usually short. The APA notes they typically last between thirty seconds and two minutes. Hydration and a position change usually settle them. Contractions that come in a regular pattern, get closer together, and don't stop with hydration are real ones — call your provider.

If you are looking at the calendar for a baby shower, week 27 to week 33 is the conventional sweet spot. You are visibly pregnant, mobile enough to enjoy it, and not yet exhausted enough to dread it.

What your partner can do

Three concrete moves for partners in the closing week of the second trimester.

The second trimester is, by consensus, the easiest one. The first is exhausting and uncertain. The third is uncomfortable and slow. The middle three months are the window in which most pregnant people feel mostly like themselves, except larger. That window closes this week. The most useful thing a partner can do is verify the on-call number for the provider is saved in both phones and works on a test call. The third trimester is when you will need it at odd hours, and the moment you need it is the wrong moment to be hunting for the right line.

Handle the registry. If you have been putting it off, this is the week. By week 30 you will be tired enough that scrolling stroller reviews on a phone in bed at 11pm will feel like a chore worth resenting. Knock it out across one Saturday afternoon, with a real conversation about what you actually want versus what the internet says you need. Two weeks of texting the same friend to ask what they used most will give you a better registry than six hours of solo research.

Start the childbirth class. The APA's specific recommendation is that childbirth classes "be completed by the time you have finished 37 weeks," and most are six weeks long. Week 27 to week 33 is the natural enrollment window. Hospital classes, hypnobirthing, Bradley method, Lamaze — pick the one that matches your worldview, sign up tonight.

And finally, on the car seat: the APA's plain warning that "the vast majority of hospitals require you to have an infant car seat before they will allow your baby to go home with you" is a sentence that has surprised many parents at week 39. Order one. Install it now. Most fire departments will inspect a car-seat install for free, and most parents install it slightly wrong the first time.

Names we love this week

The names that fit week 27 have completion in them. Names that close a chapter cleanly.

• Clara means "bright, clear" in Latin. The name has the rare quality of sounding both Victorian and post-millennial. Few names earn that across two centuries.
• Adeline means "noble" through its Germanic roots. The full form has elbowed past the diminutive Addie in popularity, which says something about where formal names are trending right now.
• Audrey — English "noble strength" — for the closing week.
• Margot is French, from the Greek for "pearl." The silent t is the whole pleasure of it. A name that looks like one thing and sounds like another.
• Arthur is the once-and-future king and one of the steadiest classic boys' names in the English-speaking world. It survived a long stretch as a grandfather name and emerged on the other side as fresh.
• Henry means "ruler of the home" in Old German. Eight kings of England, three US presidents, one American adventurer, and still climbing.
• Oliver means "olive tree" and has spent the last decade in or near the US top five for boys. The popularity does not seem to dent its appeal — children named Oliver are universally well-received by other parents.
• Cosima is Greek for "order, decency." A composer's name, a designer's name, a name that has stayed rare in the US while becoming a quiet favorite in Italy and Germany.

A small piece of advice for week 27: if you keep a journal, write one paragraph in it tonight. Just one. About what the second trimester was like, what you will miss about it, what you are quietly nervous about for the third. By the time you are nursing at 4am six months from now, you will not remember this week clearly enough to write it. The paragraph from tonight will be the only record you have.

Sources

• American Pregnancy Association — Week 27 of Pregnancy
• Cleveland Clinic — Fetal Development: Stages of Growth
• Cleveland Clinic — Fundal Height