The Main Stages of Pregnancy — The 1st, 2nd & 3rd Trimester
Despite being part of a natural and everyday process, the main stages of pregnancy still mystify people. This is no surprise, though, given that each gestational phase encompasses significant changes for both the mother and the unborn child.
Understanding the main stages of pregnancy is crucial for expectant parents. Swaddling yourself in knowledge will help you navigate the pregnancy journey with greater confidence and ease. It can also facilitate the transition to the postpartum period.
This blog post aims to detail the main stages of pregnancy. We'll focus on the key developments and changes that occur during the 1st, 2nd, and 3rd trimesters for both mom and baby.
The Pregnancy Timeline
Pregnancy is a wondrous and complex biological process and state of being. During pregnancy, a fertilized egg develops into a fetus.
This happens over the course of about nine months, with the average pregnancy being 40 weeks. Pregnancy is divided into three distinct trimesters that last 13-14 weeks each. Each trimester has distinguishing changes and milestones.
1st Trimester. The birthing parent's body is going through significant hormonal shifts. Major organs are beginning to form in the fetus.
2nd Trimester. The mother is noticing obvious physical and energetic changes as the baby quickly develops.
3rd Trimester. Both mother and child are busy preparing for the birth. While the baby is getting bigger, the mom may start to experience discomfort as delivery time nears.
The 1st Trimester (Weeks 0-13)
The 1st trimester of pregnancy is a time of major transformation. This period is crucial because it lays the foundation for the health and development of the unborn child.
What Expecting Moms Can Expect
A woman's hormones recalibrate to enable the body to support a growing fetus. Some hormone levels, such as human chorionic gonadotropin (hCG), estrogen, and progesterone surge. This spike can lead to a range of physical and emotional changes.
Common Symptoms in the 1st Trimester
Among the most common symptoms experienced during this stage are:
Morning sickness (which can actually occur anytime of day) usually shows up as nausea and vomiting. It affects many women starting at about the sixth week, peaking around the eighth or ninth week, and tapering off by the 16th or 18th week of pregnancy. While unpleasant, morning sickness generally signifies that the pregnancy is progressing as it should, as it is linked to the rise in hCG levels. Mild morning sickness is normal and presents no harm to mom or baby.
Fatigue — feeling unusually tired and lethargic — is a frequent complaint as well. The body’s increased metabolic demands and the psychological adjustment to pregnancy are likely culprits.
Pregnant people also often report breast tenderness, frequent urination, mood swings, and a general sense of upheaval as they adapt to their changed circumstances.
What's Going On with the Baby
By the end of this period:
The embryo has morphed into a fetus that’s around three inches long and weighs about one ounce.
The major organs and systems — heart, brain, spinal cord, etc. — have started forming.
The fetus has recognizable features (e.g., fingers and toes), facial characteristics, and a steady-beating heart.
The placenta, a lifeline organ between mother and child, has formed. Its job is to provide oxygen and nutrients to the baby and get rid of any waste.
The 2nd Trimester (Weeks 14-27)
The 2nd trimester of pregnancy is the most comfortable period for many expectant moms. However, this mid-pregnancy stage definitely has its share of significant body-mind transformations.
Changes in the Birthing Person
As the body continues evolving to meet the new demands of 2nd-trimester pregnancy, visible changes really blossom. The womb grows and begins to rise up from the pelvic girdle, leading to that beautiful baby bump.
Women often start feeling more energetic in the 2nd trimester and some of the discomforts associated with the 1st trimester dissipate.
The 2nd trimester often brings relief from the common 1st-trimester symptoms such as morning sickness and extreme fatigue. However, this phase is not without its own challenges.
As the baby grows, new sensations that can be both exciting and uncomfortable may arise. For example, some symptoms that may pop up in the 2nd trimester may include:
Back pain
Ligament pain (as ligaments stretch to accommodate the expanding uterus)
Increased appetite
Skin changes — pregnancy "glow" and/or pigmentation changes (e.g., linea nigra or melasma)
Quickening (feeling fetal movements)
Fetal Development Milestones
During the 2nd trimester, the fetus grows quickly and develops significantly. By the end of this trimester, the baby's going to be about 14 inches long and weigh around 2 pounds.
Other key developmental markers include:
The fetus begins to develop fine hair called lanugo.
Facial features become more distinct and the baby can make facial expressions and may start thumb-sucking.
The heartbeat gets stronger and may be audible with a stethoscope.
More complex systems, like the lungs and digestive tract, are beginning to develop.
Eyelashes and eyebrows appear.
The skin begins to form vernix caseosa, which is a protective coating.
Growth and weight gain are more noticeable.
The brain is developing fast and the senses are maturing — the fetus can respond to sounds and may even recognize voices.
The 3rd Trimester (Weeks 28-Delivery)
The last trimester means that birth is just around the corner. With the impending delivery, the birthing parent and unborn child are continuing to change and prepare so they're ready.
Changes in the Expecting Mother
As the 3rd trimester progresses, the ever-growing baby leads to an expanding belly. This can cause discomfort and mobility challenges.
Emotional zigzags are also common, as the reality of motherhood sinks in and hormones continue to fluctuate. Anxiety, along with excitement and joy, about childbirth and parenting may surface.
Strategies for Managing 3rd Trimester Discomforts
While discomfort is a hallmark of the 3rd trimester, there are plenty of ways to help address common complaints. Here are some options to get you started, but it's always a good idea to discuss specific pregnancy symptoms with a qualified healthcare provider.
Back pain. Do gentle stretching or prenatal yoga. Maintain good posture. Try heat therapy or cold packs.
Swelling in the legs and ankles. Elevate the feet, stay hydrated, and wear compression stockings and comfortable shoes.
Heartburn. Eat smaller, more frequent meals. Avoid spicy or fatty foods. Ask your care provider if over-the-counter antacids are OK.
Fatigue. Get lots of rest. Allow space and flexibility in your schedule for naps or downtime.
Braxton Hicks contractions. Hydrate. Go for a walk, move your body, or shift positions. Relax in a bath, with a nap or a massage, or by listening to calming music.
Stress and anxiety. Talk openly with partners or care providers about these feelings and concerns. Try mindfulness practices, like breathwork or journaling.
How the Baby Continues to Grow
This stage is crucial for finalizing the baby's physical development and ensuring that all systems are functioning properly before entering the world.
3rd-trimester fetal development milestones include:
Meaningful growth and weight gain continue until the fetus nears its full size (18-20 inches long) and weight (5-10 pounds).
The skin becomes smoother as the vernix caseosa thickens.
Organs are reaching full development.
Response to external stimuli (e.g., sounds and light) may happen more.
There will be less room for the baby to move, but it's still very active — possibly kicking and stretching.
The baby begins to reorient itself for birth, often settling into a head-down position.
Getting Ready for Labor & Delivery
The 3rd trimester is the perfect time to finish preparing for the baby's arrival.
We encourage expectant parents to have a birth plan that outlines labor, delivery, and immediate postpartum care needs and wishes. This plan can specify pain management choices, the presence of support persons, and newborn care preferences.
Our clients have also found childbirth education to be very beneficial. Courses provide valuable information on labor stages, pain relief options, and breathing techniques.
Continuous Care throughout Pregnancy
We cannot understate how vital consistent, high-quality prenatal care is for the well-being of both expectant mothers and their babies.
Regular check-ups and evaluations throughout all stages of pregnancy help monitor mom's health, track fetal development, and detect complications early on. This proactive, attentive approach can provide peace of mind and cultivate a nurturing environment that's ideal for the baby's growth.
Prenatal Care in Each Trimester - What to Expect
Every visit will include a physical exam and consultation to help determine the health status of the birthing person and the unborn child. The care provider will check the mother’s weight, belly size, blood pressure, and other wellness indicators as well as follow the growth and development of the fetus.
Different methods and tools are used to help care providers monitor and evaluate pregnancy progress. For example, ultrasounds enable care providers to assess anatomical development, evaluate fetal position, and check amniotic fluid levels. Blood tests are useful for detecting genetic conditions, gestational diabetes, anemia, infections, viruses, etc. Urine tests help reveal albumin and glucose, which can suggest issues like pre-eclampsia, toxemia, or hyperglycemia.
1st trimester. Care providers typically advise getting a checkup every four weeks during this stage of pregnancy. The first visit is mostly about establishing rapport and answering questions, documenting medical histories, and getting a baseline for mom and baby.
2nd trimester. Healthcare providers usually recommend monthly checkups and various screenings and tests. These visits continue monitoring the overall well-being of the birthing person and fetus as well as the baby’s growth and development.
3rd trimester. Check-ups get more and more frequent — every other, then every, week — as the due date approaches because potential complications are more likely to happen in later phases of pregnancy. The care provider is focused on helping ease maternal complaints and looking out for signs of fetal distress or early labor.
Midwives, Providing Superb Prenatal Care at Every Stage
Midwives are exceptionally well-qualified to care for you during all the main stages of pregnancy. They specialize in providing comprehensive prenatal services and are skilled in monitoring the progress of pregnancy, offering essential screenings, and educating clients on diet, exercise, childbirth, and more.
Better still, midwives advocate for an empowering birth experience. They prioritize:
Establishing trusting relationships with expectant mothers (and their partners/families!)
Encouraging birthing parents to actively participate in decision-making
Making sure clients feel informed, respected, and confident during their pregnancy
Offering a holistic approach to maternal health, integrating physical, emotional, and social support
Providing continuous support throughout labor and delivery
Tailoring care to each individual's needs and preferences
Questions about Pregnancy? Our Midwives Can Help!
By gaining insights into the main stages of pregnancy, expectant mothers can better prepare themselves for the physical, emotional, and lifestyle changes that accompany each trimester. Stay informed, seek support from healthcare providers, and cherish the miraculous journey of bringing new life into the world.
Having a certified midwife on your prenatal care team can enhance your pregnancy experience. If you're interested in learning more, don't hesitate to reach out. We're here to help!