7th week: Arms and legs start to grow

Weeks and days
6+0 to 6+6
Month
2
Trimester
1

This week, the embryo grows to 4 to 7 millimeters long. Arm and leg buds grow, and the eyes begin to form. On ultrasound, the embryo and heartbeat can now usually be seen.

A single lentil lies in an open palm on beige linen
Lentil3 to 8 mm, the size of your baby this week

Week 7 of 40

Calculate your week
1st trimester2nd trimester3rd trimester

How big is the embryo?

0246810121416 mm5th week0.2 to 2.56th week1.5 to 57th week4 to 78th week10 to 15Lentil at the same scale

4 to 7 mm

The arm buds are joined by the leg buds, and the arms now look like little paddles. The lens and optic cup begin to form.

Length according to the Carnegie stages of embryology. On ultrasound, the crown-rump length at the end of the week is about 7 mm.

This week

Your baby

  • Leg buds grow, and the arms look like little paddles.
  • The lens and optic cup begin to form.
  • The heart beats about 100 to 120 times per minute.

Your body

  • The median hCG level is 3,339 mIU/ml; 158 to 31,795 is normal. More in the hCG levels chart.
  • Nausea usually still increases and is strongest around the 9th week.
  • Bleeding is most common between the 5th and 8th week. If you have pain or heavy bleeding, get examined.

What matters now

  • Keep taking folic acid and iodine, folic acid until the end of the 12th week of pregnancy.
  • First basic ultrasound: in Germany between 8+0 and 11+6, in Austria between the 8th and 16th week of pregnancy, in Switzerland in the 12th to 14th week.
  • After IVF, the first ultrasound at the fertility clinic is usually at around 7+0.

Get checked right away: one-sided pain in the lower abdomen, heavy bleeding, pain in the tip of the shoulder, or dizziness. This can be a sign of an ectopic pregnancy.

Gestational sacYolk sacEmbryo with heartbeat

On ultrasound

  1. 5+6

    Heartbeat was visible from this point in all women with a reliable date.

  2. 6+0

    Embryo is to be expected from now on.

  3. 6+2

    Heart rate is usually at least 120 beats per minute from this point.

From a length of 7 mm, the heart should be visibly beating. If there is no heartbeat then, a second doctor looks at the image, or another ultrasound follows after 7 days at the earliest. Only then is the diagnosis certain.

Frequently asked questions about the 7th week of pregnancy

How big is the baby in the 7th week of pregnancy?

4 to 7 mm, about the size of a lentil. On ultrasound, the crown-rump length at the end of the week is about 7 mm.

How fast does the heart beat in the 7th week of pregnancy?

About 100 to 120 times per minute. From 6+2, at least 120 beats are considered normal. The heart reaches the often-quoted 160 beats only a few weeks later.

When is the first ultrasound at the gynecologist?

In Germany, the first ultrasound screening takes place between 8+0 and 11+6. Health insurance pays for an earlier ultrasound only if a disrupted early pregnancy is suspected.

Which month is the 7th week of pregnancy?

The 2nd month of pregnancy, in the 1st trimester. Figures such as 6+4 weeks also belong to the 7th week of pregnancy.

Sources

Updated on 27 October 2026 · Fertilio Editorial Team