This week your baby is a rapidly dividing ball of cells called a blastocyst. It burrows into the lining of your uterus in a step called implantation. The inner cells become the embryo, and the outer layer begins to form the placenta. [1]
Once the fertilized egg attaches to the uterine wall, the placenta starts making a hormone called human chorionic gonadotropin (hCG). As the pregnancy continues, hCG rises quickly. It signals your ovaries to stop releasing eggs and to make more estrogen and progesterone. [1]
A missed period is one of the most common early signs of pregnancy. Others include tender or swollen breasts and fatigue, which is linked to a rapid rise in progesterone. [2]
You can also be pregnant without many typical symptoms. Mayo Clinic suggests taking a home pregnancy test or seeing a provider when you miss a period, whether or not other signs are present. So if you feel nothing much yet, that is common too. [2]
Some people notice light spotting known as implantation bleeding. It can be one of the first signs of pregnancy and happens when the fertilized egg attaches to the uterine lining, about 10 to 14 days after conception. [2]
Bleeding in the first trimester is more common than many people expect. It happens in about 15 to 25 of every 100 pregnancies, and in many cases it does not signal a serious problem. [3]
Not sure about your exact week?
Type your due date, get your week in one tap. Free, no signup.
Open the week calculatorStart a daily prenatal vitamin now if you have not already. The CDC recommends 400 mcg of folic acid every day for anyone who can become pregnant, to help prevent serious birth defects of the brain and spine (neural tube defects). [4]
Timing is the reason this matters this week. Because neural tube defects form very early in pregnancy, the CDC advises taking 400 mcg of folic acid starting at least one month before pregnancy and continuing through the first three months. [5]
There is no known safe amount of alcohol during pregnancy and no safe time to drink. All types, including wine, beer, and liquor, can harm the baby, and it is never too late to stop. [6]
Smoking during pregnancy raises the risk of preterm delivery, restricted fetal growth, and infant death. Quitting at any point during pregnancy helps protect both you and your baby. [7]
You do not have to give up coffee entirely. ACOG states that moderate caffeine of less than 200 mg per day, about one 12 ounce cup of coffee, does not appear to be a major contributing factor in miscarriage or preterm birth. [8]
At 4 weeks, mild cramping and light spotting are common. Most of what you feel right now is normal. A few signs deserve a call, so you never have to wonder. [3]
Sharp or severe pain on one side of your lower belly, especially with dizziness, feeling faint, or pain in the tip of your shoulder: go to emergency care now or call 911. [9]
Bleeding that soaks through a pad, or heavy bleeding with cramping: call your provider today. If the bleeding is heavy and you also feel faint or the pain is severe, go to emergency care now. [10]
Any vaginal bleeding during pregnancy is worth a call. ACOG advises contacting your ob-gyn about it so the cause can be checked. [3]
A temperature of 100.4 F (38 C) or higher, chills, or pain when you pee: call your provider today. [11]
Vomiting so often that you cannot keep liquids down, or signs of dehydration such as dark urine, dizziness, or peeing much less than usual: call your provider today. [12]
Leelalu is education, not medical care. Nothing here is a diagnosis. For anything on this list, or any symptom that worries you, contact your provider. If it feels like an emergency, call 911.
Your next step is booking care. March of Dimes advises calling your provider for your first prenatal checkup as soon as you know you are pregnant, with routine checkups then scheduled about every 4 weeks through week 28. [14]
As you move toward week 5, it helps to hold the big picture gently. Early pregnancy loss is common, occurring in about 10 percent of clinically recognized pregnancies, which means the large majority of recognized pregnancies continue. And about half of early losses come from random chromosomal differences, generally not caused by anything a parent did. [15]
Yes. You can be pregnant without many typical symptoms. Mayo Clinic suggests taking a home test or seeing a provider when you miss a period, whether or not other signs are present. [2]
Yes. A pregnancy test looks for hCG, which the placenta starts making after the egg attaches to the uterus, as early as about 10 days after conception. Home tests are about 97 to 99 percent accurate a week or two after a missed period, so retest in about a week if an early result is negative. [13]
This week your baby is a tiny ball of cells called a blastocyst, just settling into the lining of your uterus and beginning to form the embryo and placenta. [1]
LEELALU is education, not medicine. This page cannot diagnose or treat anything, and it never replaces your clinician. For anything on the "call your doctor" list, or anything that worries you, contact your provider. Found an error? Write to hello@leelalu.com and a person will read it. Our method: Editorial Standards.