At 13 weeks of pregnancy, the fetus is about 7–8 cm long, with formed fingers, active movement, and a lower risk of miscarriage.

Counting about two weeks from the first day of your last period gives a rough estimate of your conception date in a regular 28-day cycle.

Most pregnancies last about 40 weeks, so your due date is roughly 280 days from the first day of your last menstrual period.

At 18 weeks, your baby usually measures about 14–22 cm long and 190–220 grams, about the size of a bell pepper or sweet potato.

Those first trimester weeks bring fast changes to your body and baby, so early checkups, vitamins, rest, and gentle movement matter a lot.

At 13 weeks of pregnancy, the fetus measures about 7–8 cm crown-to-rump and weighs roughly 20–25 grams.

A rectal temperature of 100.4°F (38°C) or higher in a baby under 3 months needs urgent medical assessment, even if other signs seem mild.

Weekly fetal growth describes how a tiny cluster of cells becomes a full-term baby with forming organs, senses, and steady length and weight gains.

At 12 weeks, the baby is plum-sized with formed organs, distinct facial features, and active movement inside the uterus.

Fluid around a baby’s heart on ultrasound often reflects a small pericardial effusion that can be temporary or a sign of other conditions.