How is the due date calculated?

Due date calculation typically uses Naegele's rule, where you take the first day of your last menstrual period, add one year, subtract three months, and add seven days. For example, if the first day of your last period was June 1st, your due date would be March 8th of the following year. This is equivalent to adding 280 days to the first day of your last period. This method assumes a 28-day menstrual cycle with ovulation occurring on day 14.

What conditions are considered high-risk pregnancies?

A high-risk pregnancy indicates a higher probability of complications. Factors that may increase risk include: being very young or over 35, being overweight or underweight, having had problems in previous pregnancies, pre-existing health conditions (like high blood pressure, diabetes, autoimmune diseases), and carrying twins or multiples. Conditions like gestational diabetes or preeclampsia that develop during pregnancy can also lead to high-risk status. If you have concerns about high-risk pregnancy, consult your doctor.

How often should prenatal check-ups be scheduled?

According to the Office on Women's Health, the recommended frequency for normal prenatal check-ups is: once a month between weeks 4 and 28, twice a month between weeks 28 and 36, and once a week from week 36 until delivery. Women with high-risk pregnancies may need more frequent prenatal care and monitoring.

Due Date Calculator

Calculate your due date and track pregnancy progress

First day of last period：

About the Due Date Calculator Features:

Enter your last menstrual period date to automatically calculate due date
Display current pregnancy week and days
Interactive pregnancy calendar clearly marking important dates
Easily view past and future pregnancy progress by month

How Pregnancy Weeks Are Calculated

Pregnancy is calculated starting from the first day of your last menstrual period, with the due date approximately 40 weeks later. Therefore, by the time most women know they're pregnant, they're typically at week 5 or 6. If you're planning for pregnancy, it's recommended to use your phone's 'Health' app to record your menstrual cycles. During your first obstetrics visit, the doctor will usually ask for the first day of your last period to calculate your due date.

Due Date Calculation Method

Pregnancy due date calculation typically uses Naegele's rule, a method invented by German obstetrician Franz Karl Naegele.

The calculation is based on the first day of the Last Menstrual Period (LMP), adding one year, subtracting three months, and adding seven days to obtain the Estimated Date of Delivery (EDD).

For example, if the first day of your last period was June 1st, "subtract three months, add seven days, and add one year" results in March 8th of the following year.

Generally, the due date is about 40 weeks, so adding 280 days to the first day of your last period yields the same result as Naegele's rule. This is the Estimated Date of Delivery (EDD).

Note: This method assumes a 28-day menstrual cycle with ovulation and fertilization occurring on day 14.

Pregnancy Precautions

Pregnancy can be divided into three stages: the first trimester (before 13 weeks), the second trimester (13-29 weeks), and the third trimester (over 29 weeks).

Regular prenatal check-ups
Wear breathable, comfortable maternity clothes
Maintain a positive mood
Avoid secondhand smoke exposure

First Trimester (Before 13 weeks)

Diet

Folic acid supplements
Avoid raw food
8 glasses of water daily

Managing Discomfort

Relieving morning sickness
Managing frequent urination

Exercise

Gentle walking
Prenatal yoga

Second Trimester (13-29 weeks)

Diet

Increase protein intake
Supplement calcium and iron

Weight Management

Weekly weight gain of 0.3-0.5kg

Skin Care

Prevent stretch marks
Manage itching

Third Trimester (Over 29 weeks)

Diet

Small, frequent meals
Avoid excessive weight gain

Sleep

Left side sleeping position
Use a pregnancy pillow

Monitoring

Count fetal movements
Watch for swelling

Regular Prenatal Check-ups

During pregnancy, regular prenatal check-ups help diagnose the health of both mother and baby, promptly identify any issues (if they arise), and prevent complications during delivery.

According to theOffice on Women's Health (OWH, part of the US Department of Health and Human Services)the recommended frequency for normal prenatal check-ups is:

Between weeks 4 and 28, once a month
Between weeks 28 and 36, twice a month
From week 36 until delivery, once a week

Note: Women with high-risk pregnancies may need more frequent prenatal care.

High-Risk Pregnancy

A 'high-risk pregnancy' doesn't necessarily mean problems will occur, but rather indicates a higher probability of complications. According to theOffice on Women's Health (OWH)the following factors may increase the risk of problems during pregnancy:

Being very young or over 35 years old
Being overweight or underweight
Having had problems in previous pregnancies
Pre-existing health conditions such as high blood pressure, diabetes, autoimmune diseases, cancer, and HIV
Carrying twins or multiples

Health issues that may lead to high-risk pregnancy can also develop during pregnancy, such as gestational diabetes or preeclampsia.

If you have any concerns about high-risk pregnancy, consult your doctor, who can explain the level of risk and the actual likelihood of problems occurring.