The first trimester (weeks 0-13) is generally considered the riskiest because it's when the baby's vital organs and body structures form, making it most vulnerable to major birth defects from harmful exposures (like alcohol, certain medications, infections) and the time when most miscarriages occur. While risks decrease after the first trimester, complications like preterm birth and gestational diabetes can arise later, and the third trimester brings physical discomfort as the body prepares for labor.
The third trimester is the final stage of pregnancy and can be considered to be the most painful. During this stage, your baby is getting bigger, which puts more stress on your body that causes aches and discomfort.
Most miscarriages happen in the first 12 weeks of pregnancy (known as early miscarriage). It is estimated that early miscarriages happen to 10-20 in 100 (10 to 20%) of pregnancies. It is estimated that second trimester loss (late miscarriage) happens to 3-4 in 100 (3 to 4%) of pregnancies.
From a medical point of view, at 12 weeks a pregnancy is generally considered to be "safe". While a miscarriage (or later, stillbirth) can happen at any point during gestation, the odds are highest in the first trimester.
During the first trimester, the fetus is most susceptible to damage from substances, like alcohol, drugs and certain medicines, and illnesses, like rubella (German measles).
Gestational diabetes. Low birth weight. Multiple gestation (pregnancy with more than one fetus, such as twins or triplets). Gestational hypertension, preeclampsia, and eclampsia.
Second trimester (week 13–week 28)
Most women find the second trimester of pregnancy easier than the first. But it is just as important to stay informed about your pregnancy during these months. You might notice that symptoms like nausea and fatigue are going away.
Some call the second trimester the "golden trimester" because early pregnancy symptoms, like nausea and fatigue, usually go away. You may not have the pain, anxiety, and insomnia that often come with the third trimester. In other words, the second trimester is often the most energetic and pleasant one.
For pregnancies observed at 5 weeks, 20% of the pregnancies miscarried. As pregnancy goes on, miscarriage rates go down — they are down to 1% to 2% by the end of the first trimester. Although second-trimester miscarriages do happen, they are much less common.
The “fourth trimester” concept, defined as the first 12 weeks after delivery (and beyond), is a critical window of time for clinicians to intervene to optimize women's cardiovascular health after pregnancy.
Chromosome conditions
If your baby inherits a chromosome condition, they'll not be able to develop properly. This causes a miscarriage. It's not possible to tell which parent passed on the chromosome condition. Chromosome conditions are thought to be the most common cause of an early miscarriage.
Top 5 Conditions of Abnormal Pregnancy
Most miscarriages happen in the first trimester, especially between weeks 6 and 8, with the risk decreasing significantly as the pregnancy progresses, particularly after a heartbeat is detected. About 80% of losses occur before 12 weeks, and the rate drops sharply after week 12, with a very low risk after 16 weeks.
The second trimester of pregnancy is often the most enjoyable. Find out how to relieve common symptoms — and consider ways to prepare for what's ahead. The second trimester of pregnancy often brings a renewed sense of well-being. The worst of the nausea often is gone.
Most miscarriages happen during the first trimester of pregnancy, which is about the first 13 weeks.
There's no perfect time to share your pregnancy—do what feels right for you. Many wait until after the first trimester. Miscarriage risk drops after 13 weeks, but it's also OK to tell trusted loved ones earlier for support.
Folic acid supplements can help your baby's brain, skull and spinal cord develop properly and prevent developmental conditions such as spina bifida from occurring. Taking folic acid a day three months before conception and until your 12th week of pregnancy could reduce your chances of miscarriage.
The most common sign of miscarriage is vaginal bleeding.
This can vary from light spotting or brownish discharge to heavy bleeding and bright-red blood or clots. The bleeding may come and go over several days.
There is no evidence of reduction in the risk of miscarriage in women prescribed bed rest. HCG administration as an alternative care for threatened miscarriage was more effective than bed rest in the Harrison study but this benefit is not confirmed when compared with placebo.
The "3-2-1 Rule" in pregnancy is a guideline for first-time mothers to know when to call their midwife or doctor for active labor: consistent contractions that are 3 minutes apart, lasting 2 minutes each, for 1 hour (or sometimes cited as 3-1-1, meaning 3 minutes apart, 1 minute long, for 1 hour). For subsequent pregnancies, the 5-1-1 Rule (5 minutes apart, 1 minute long, for 1 hour) is often used, indicating labor is progressing more quickly.
For most people, the extreme fatigue of the first trimester is soon forgotten. That's because the second trimester often comes with a glow and a boost in energy. So don't worry if it seems like all you're doing these first few weeks is lying around, dozing, or napping. This is normal.
For example, you shouldn't clean a litter box due to the risk of toxoplasmosis. You should also avoid lying on your back for extended periods of time. At nighttime, sleep on your side instead of your back, as this is best for your circulation. Don't stress if you wake up and find yourself on your back.
You've made it to your last trimester. The third trimester is the shortest, and includes weeks 28-40. We're sure you're feeling all kinds of emotions now that you get to meet your baby soon! During these last few months, it is time to organize everything before your baby gets here.
Week 7: The head develops
Seven weeks into pregnancy, or five weeks after conception, your baby's brain and face are growing. Depressions that will give rise to nostrils become visible. The start of the eyes' retinas form. Lower limb buds appear that will become legs.
The size and shape vary between pregnancies, but consistent growth is a good sign. Fewer early symptoms: Nausea and fatigue usually ease up, allowing you to feel more like yourself. Increased appetite: Your body needs more calories and nutrients to support your growing baby, and feeling hungrier is common.