Understanding Your Baby’s Due Date in Grand Rapids, Michigan

In Grand Rapids, many expecting parents receive their prenatal care through Spectrum Health, Trinity Health Grand Rapids, Metro Health, Mercy Health, or local OB/GYN clinics. No matter where you receive care, understanding how your baby’s due date is calculated can help you feel more prepared throughout pregnancy.

This guide explains how due dates are estimated, how ultrasounds are used, and what “premature” and “overdue” mean, with information tailored to families in Grand Rapids, MI.

How Pregnancy Length and Due Dates Are Calculated

Average Length of Pregnancy

• The average length of human pregnancy (gestation) is about 40 weeks (280 days).
• This 40-week count starts from the first day of your last menstrual period (LMP), not from the actual day of conception.
• Conception usually happens about 2 weeks after your period starts, and the fertilized egg then takes 5–7 days to implant in the uterus.

So while your baby spends roughly 37 weeks in the uterus, the pregnancy is counted as 40 weeks from your last period.

What Is a “Full-Term” Pregnancy?

Because cycles can vary and some people in Grand Rapids have irregular periods, doctors use a range:

• Full term: Birth between 37 and 42 weeks
• Premature (preterm): Birth before 37 weeks
• Overdue (post-term): Pregnancy that continues beyond 42 weeks

The medical term for your due date is Estimated Date of Confinement (EDC) or Estimated Due Date (EDD).

How Likely Is It That You’ll Deliver on Your Due Date?

Even with careful calculation:

• Only about 4% of pregnant people give birth exactly on their due date.
• Most babies in Grand Rapids arrive within two weeks before or after the estimated due date.

Your EDD is an important guide for planning prenatal care, scheduling tests, and preparing for delivery at your chosen Grand Rapids hospital or birth center.

How to Calculate Your Baby’s Due Date

Simple Due Date Calculation (LMP Method)

If you know the first day of your last menstrual period, you can estimate your due date at home:

1. Take the first day of your last period.
2. Add 7 days.
3. Add 9 months.

Example:

• First day of last period: February 1
• Add 7 days: February 8
• Add 9 months: Due date = November 8

This is a rough estimate. Your OB/GYN, midwife, or family doctor in Grand Rapids will refine this using your medical history and ultrasound measurements.

When Your Periods Are Irregular

Many people in West Michigan have irregular menstrual cycles, especially during times of stress, weight change, or hormonal imbalance. This can make it hard to know when you conceived.

In these cases, your provider may:

• Ask about when you first felt fetal movements (quickening) – a very rough guide.
• Rely more heavily on early pregnancy ultrasounds, especially between 6 and 12 weeks, to estimate gestational age.
• Perform a pelvic exam to assess the size of your uterus.

If your cycles are irregular, it’s especially important to start prenatal care early with a Grand Rapids provider so your due date can be estimated as accurately as possible.

Using Ultrasound to Determine Baby’s Due Date

What Is a Pregnancy Ultrasound?

A pregnancy ultrasound is a non-invasive test that uses high-frequency sound waves to create images of your baby and reproductive organs. Ultrasounds are commonly performed at:

• Spectrum Health and Corewell Health imaging centers
• Trinity Health Grand Rapids
• Metro Health and Mercy Health facilities
• Independent imaging centers throughout Kent County

What Happens During an Ultrasound?

The general steps:

1. You lie on an exam table.
2. A small amount of clear conductive gel is applied to your abdomen.
3. The technician (sonographer) places a hand-held device called a transducer on your abdomen.
4. The transducer is moved across your skin to capture images.
5. Sound waves bounce off internal structures (including your baby) and return to the transducer.
6. A computer converts these sound waves into a two-dimensional image on a monitor.

You will not feel or hear the sound waves themselves.

How Ultrasound Helps Estimate Gestational Age

During the scan, the sonographer measures key parts of your baby’s body, such as:

• Head circumference
• Abdominal circumference
• Length of long bones (like the femur)

These measurements are compared to standard growth charts to estimate:

• Gestational age
• Estimated due date (EDD)

Early ultrasounds (around 6–12 weeks) are usually the most accurate for dating a pregnancy. Later ultrasounds can still be helpful but are slightly less precise for estimating due dates.

Other Diagnostic Uses of Pregnancy Ultrasound

Beyond estimating your baby’s due date, pregnancy ultrasound is used to check for:

• Multiple fetuses (twins, triplets, etc.)
• Health problems with the baby, such as structural abnormalities
• Ectopic pregnancy (when the embryo implants in the fallopian tube instead of the uterus)
• Placental problems, such as:
  • Placenta previa – placenta covering or near the cervix
  • Other placental abnormalities
• Health of the mother’s reproductive organs, including the uterus and ovaries

If any concerns are found, your Grand Rapids provider may refer you to a maternal-fetal medicine specialist at a major local hospital.

Premature Babies (Preterm Birth)

A baby born before 37 weeks of pregnancy is considered premature.

Survival and Health Outcomes

• The closer to full term your baby is at birth, the better the chances of survival and long-term health.
• After about 34 weeks gestation, with good neonatal and pediatric care (widely available at major Grand Rapids hospitals), almost all babies survive.
• Premature babies are more likely to have:
  • Breathing (respiratory) difficulties
  • Increased risk of infection
  • Other issues related to immature organs

Neonatal Intensive Care Units (NICUs) at Spectrum Health, Trinity Health Grand Rapids, and other regional centers are equipped to care for premature infants from across West Michigan.

Possible Risk Factors for Premature Labor

Often, no clear cause is found. However, factors that can increase the risk of preterm birth include:

• Smoking during pregnancy
• Drinking alcohol or using certain drugs during pregnancy
• Low body weight before pregnancy
• Inadequate weight gain during pregnancy
• No or late prenatal care
• Significant emotional stress
• Placental problems, such as placenta previa
• Certain chronic diseases, including:
  • Diabetes
  • Congestive heart failure
• Infections, such as syphilis and other sexually transmitted infections

In Grand Rapids, the Kent County Health Department and Grand Rapids Public Health offer resources for smoking cessation, prenatal care referrals, and STD testing to help reduce these risks.

Overdue Babies (Post-Term Pregnancy)

An overdue or post-term pregnancy continues beyond 42 weeks.

• About 5 out of every 100 babies will be over 42 weeks gestation.
• If you go one week past your due date without signs of labor, your doctor or midwife will usually monitor you more closely.

Why Monitoring Is Important

As pregnancy goes past term:

• The placenta may start to deteriorate after about 38–40 weeks, which can:
  • Reduce the baby’s oxygen and nutrient supply
• The baby may grow too large for a safe vaginal delivery, increasing the risk of:
  • Birth injuries
  • Cesarean section (C-section)

Tests for Overdue Pregnancy

If you are overdue, your Grand Rapids provider may recommend:

• Ultrasound scans to:
  • Check the amount of amniotic fluid
  • Assess the placenta
  • Monitor baby’s growth
• Fetal heart rate monitoring using a cardiotocograph (CTG) machine

These tests help determine whether it’s safer to wait for labor to start naturally or to induce labor.

Inducing Labor for an Overdue Baby

If your pregnancy goes about 2 weeks past your due date, your healthcare provider may recommend induction of labor.

Common Methods of Labor Induction

1. Vaginal prostaglandin gel

   • A gel applied in the vagina to soften and open the cervix (cervical ripening).

2. Amniotomy

   • Also called artificial rupture of membranes (ARM).
   • Your provider uses a small instrument to break the amniotic sac (“water”).

3. Oxytocin (Pitocin)

   • A synthetic form of the hormone oxytocin given intravenously (IV).
   • Stimulates uterine contractions to start or strengthen labor.

Your OB/GYN or midwife in Grand Rapids will explain the benefits and risks of each method and tailor the plan to your medical history and baby’s condition.

Local Factors That Can Affect Pregnancy in Grand Rapids

Living in West Michigan can influence your pregnancy experience:

• Cold, snowy winters:
  • Increased risk of slips and falls on ice – wear proper footwear and walk carefully.
  • Less sunlight can contribute to low vitamin D levels; your provider may recommend supplements.
• Seasonal illnesses:
  • Flu, RSV, and other respiratory infections are more common in colder months.
  • Talk to your provider about flu shots and other recommended vaccines during pregnancy.
• Great Lakes climate:
  • Rapid weather changes can affect joint pain, swelling, and comfort during late pregnancy.

Local providers are familiar with these seasonal issues and can offer Michigan-specific guidance to keep you and your baby healthy.

Where to Get Help in Grand Rapids, MI

If you’re pregnant, planning a pregnancy, or have questions about your baby’s due date, you can reach out to:

• Your GP / Primary Care Provider
• Obstetrician–Gynecologist (OB/GYN)
• Certified Nurse-Midwife or Midwifery Practice
• Grand Rapids hospitals and health systems:
  • Spectrum Health / Corewell Health
  • Trinity Health Grand Rapids
  • Metro Health
  • Mercy Health
• Kent County Health Department
  • Prenatal care referrals
  • WIC (Women, Infants & Children) nutrition support
  • Smoking cessation and vaccination programs
• Local maternal and child health services
  • Community health centers
  • Grand Rapids Public Health programs for families

Early and regular prenatal care is the best way to confirm your due date, monitor your baby’s growth, and manage any risks throughout pregnancy in Grand Rapids, Michigan.