Week 7: An Inch Long and Weighing Less Than an Aspirin

By week 7 the embryo has crossed an inch in length and weighs less than an aspirin. The American Pregnancy Association says elbows and toes are visible now, and the trunk is starting to straighten out. The American Pregnancy Association puts the number precisely: "approximately an inch (2.54 centimeters) long by the end of this week and weighs less than an aspirin". An aspirin weighs about a third of a gram. The embryo is, by any reasonable measure, still essentially weightless, but the linear growth rate is staggering. The sweet pea of last week has become a small jellybean with the early structure of a face.

This is also the week the embryo's torso begins to straighten. Until now the embryo has been curled into a tight C-shape, with the head and the tail nearly touching. The APA notes that "the elbows and toes are more visible as the trunk begins to straighten out". The body is unfolding. By the end of next week the embryo will look recognizably human in proportion, if not in detail.

This week

The major developmental story of week 7 is detail. The APA describes it cleanly: "the hair and nipple follicles are forming, and the eyelids and tongue have begun developing". The eyelids are a thin membrane of tissue that will fuse shut next week and stay fused until around week 26 or 28. Hair follicles are dotting the scalp in their final density, most of the hair follicles a person will ever have are already in place by this week, though they won't produce visible hair until later in the pregnancy.

The Cleveland Clinic describes week 7 more concretely on the structural side: "bones begin replacing soft cartilage and genitals begin to form". The skeleton at this point is still mostly cartilage, a flexible, springy template, but ossification (the conversion of cartilage to bone) begins at specific centers and progresses outward. The Cleveland Clinic also notes that the embryo's head is disproportionately large at this stage. The head accounts for nearly half of the embryo's total length, a proportion that will gradually correct over the next thirty-three weeks. Newborns still have proportionally large heads relative to adults; the trajectory begins this week.

Organ formation is, broadly, on schedule. The APA states that "every essential organ has begun to form in the embryo's tiny body". The kidneys are forming. The pancreas is forming. The intestines are forming, initially as a loop that protrudes into the umbilical cord, they'll be drawn back into the abdomen by week 10.

Heartbeat by week 7 has climbed from last week's 110-130 BPM to roughly 130-150 BPM and will continue climbing toward a peak of around 170 BPM at week 9. An ultrasound this week will show a more developed embryo than last week's, recognizably a small body with a head, a trunk, and limb buds, with the heart visibly flickering. The yolk sac is still attached but starting to shrink as the placenta takes over more of the nutritional work.

What's happening in your body

Week 7 is, for most people, the week morning sickness peaks or is approaching peak. The next two weeks are typically the worst. If you have not been hit by it yet, you may be in the lucky 20 to 30 percent who never experience significant nausea, or you may be about to be hit hard. Either way, plan for the worst case for the next month. The relief, when it comes, is gradual and usually arrives somewhere between weeks 12 and 14.

The practical strategies that work: small frequent meals (every two to three hours), bland carbohydrate-rich snacks (crackers, toast, plain rice), protein in small doses, ginger in any form (tea, candy, ginger ale that contains actual ginger), cold foods rather than hot ones, and hydration in small sips rather than large glasses. Vitamin B6 (10-25 mg three times a day) has good evidence behind it and is over-the-counter. Unisom (doxylamine) combined with B6 is the basis for Diclegis, a prescription antiemetic considered safe in pregnancy, ask your provider if your nausea is interfering with daily life.

Severe nausea and vomiting that prevents you from keeping fluids down for more than 24 hours is hyperemesis gravidarum, and it warrants a call to your provider. If you are tracking lists at all, the names you reach for at your worst moments tell you something about which ones are sticky and which ones are placeholders. The patterns in baby-name regret lean on exactly that distinction. The Cleveland Clinic and other major bodies consider it a treatable medical condition, not a moral failing. About 1 to 3 percent of pregnancies meet the diagnostic criteria, and treatments have improved substantially in the last decade. There is no reason to suffer through it without help.

The APA notes that maternal blood volume increases by 40 to 50 percent during the first trimester — a process that begins this week and continues through week 30. The cardiovascular changes drive much of the first-trimester fatigue. The heart is working harder. The kidneys are filtering more. The result is sleep that feels less restorative than it should and an afternoon energy crash that's hard to talk yourself out of.

One practical note: if you have a routine medication you take daily, this is a good week to confirm with your provider that it's safe to continue. Most common medications are; some are not. The conversation is one phone call. Stopping a medication abruptly without that conversation is more risky than continuing one that turns out to be fine.

What your partner can do

Week 7 is one of the hardest weeks of the first trimester. The nausea is real, the fatigue is constant, and the asymmetry between partners is at its peak. The pregnancy is not yet visible, which means the work she is doing is invisible to most of the world, including, sometimes, to you.

Become the cook. Not the occasional dinner cook — the default cook. Most pregnant people in week 7 have a list of three to six foods they can tolerate and a list of every other food, which they cannot. The list changes weekly. Your job is to memorize the current list and not take aversions personally when last week's safe food becomes this week's trigger.

Drive to appointments. The first prenatal visit is likely happening in the next one to three weeks. Take the morning off. Sit in the room. Hear the heartbeat with her. The first audible heartbeat is one of two or three moments in pregnancy people remember in vivid detail twenty years later. Be there for it.

Handle the social calendar. Saying no to plans is exhausting when you also have to explain why. Take that off her plate. If you're not yet telling people, tell them you both have a stomach bug or you're slammed at work. If they push, push back. She doesn't owe an explanation for declining a Thursday-night dinner, but she will spend hours feeling guilty if she has to be the one declining.

Names we love this week

The names that suit week 7 are detailed — small, specific, distinct.

• Mia — Italian/Scandinavian "mine, beloved" — small and exact for week 7.
• Lily is a specific flower with a specific shape. The name has the precision week 7 is making in the embryo.
• Mateo — Spanish form of Matthew, "gift of God" — fresh for the inch-long week.
• David — Hebrew "beloved". A clean candidate for week 7.
• Matteo — Italian "gift of God". A clean candidate for week 7.
• Hannah — Hebrew "grace, favor". A clean candidate for week 7.
• Felix is Latin for happy or fortunate. The seventh week with a steady heartbeat and a measurable inch of body is a fortunate week by any standard.
• Elizabeth — Hebrew "God is my oath". A clean candidate for week 7.

One piece of advice for week 7: keep a single small notebook by the bed. Note the morning's symptoms, what you ate, what helped, and what didn't. By week 12 you'll have three weeks of data that will tell you exactly what works for your nausea. The patterns are individual. Most people never write them down and end up rediscovering the same hacks every few days. The notebook saves you that lap.

Sources

• American Pregnancy Association — 7 Weeks Pregnant
• American Pregnancy Association — 8 Weeks Pregnant
• Cleveland Clinic — Fetal Development: Stages of Growth