Pregnancy Terms: A Parenting Dictionary

Pregnancy is described with dozens of terms, from "gestational age" to "skin-to-skin contact." These terms are used not to complicate matters, but to clarify decisions: when to have screenings, how to assess fetal growth, when to go to the hospital, what methods of pain relief to choose. Correct definitions save time and reduce the risk of errors. The key idea is simple: each term is tied to specific weeks, examinations, or clinical steps. [1]

The terms are divided into several sections. The first is the pregnancy calendar and how to accurately calculate the due date. The second is fetal anatomy and development in simple terms. The third is screenings and mandatory tests by trimester. The fourth is ultrasound biometry and protocol terms. The fifth is the placenta and Rh factor. The sixth is the signs of labor and pain relief methods. The seventh is terms used in the delivery room and the first minutes of a baby's life. [2]

The main principle of modern obstetrics is reliance on the standards of major specialized organizations. This material draws on recommendations from authoritative sources and the latest updates where relevant for choosing a strategy. It does not replace an in-person consultation, but it helps understand the rationale behind the tests and procedures prescribed. [3]

Pregnancy calendar and gestational age

Gestational age is the period from the first day of the last menstrual period, expressed in weeks and days. For clinical purposes, the gestational age must be confirmed by an early ultrasound: measuring the crown-rump length in the first trimester is the most accurate for dating. If there is no definitive ultrasound confirmation by 22 weeks, the pregnancy is considered suboptimally dated. [4]

The estimated date of delivery is the estimated end date of a full-term pregnancy. It is recorded as the "best obstetric estimate" based on the last menstrual period and an early ultrasound, and is subsequently changed only in exceptional cases, with documentation of the reasons. This is important for planning screenings and accurately interpreting fetal growth. [5]

The concept of "full-term" has been clarified: from 37 weeks, there is no longer a "single term" but several clinical categories. Early full-term is 37 weeks 0 days to 38 weeks 6 days. Full-term is 39 weeks 0 days to 40 weeks 6 days. Late full-term is 41 weeks 0 days to 41 weeks 6 days. After 42 weeks, there is post-term pregnancy. These categories are associated with different risks for the newborn. [6]

Trimesters are often described as three blocks of time: the first until 13 weeks 6 days, the second until 27 weeks 6 days, and the third until delivery. The terms "early," "full," and "late" full-term help weigh the need for induction, planning a cesarean section, and assessing the newborn's readiness for independent life. [7]

Table 1. Calendar terms of pregnancy

Term	Definition
Gestational age	Period from the first day of the last menstrual period, confirmed by early ultrasound
Estimated date of birth	The best obstetric calculation of the end date of pregnancy
Early full-term	37 weeks 0 days - 38 weeks 6 days
Full term	39 weeks 0 days - 40 weeks 6 days
Late full-term	41 weeks 0 days - 41 weeks 6 days
Post-term pregnancy	42 weeks 0 days and beyond

Child development in simple terms: from embryo to fetus

From the first weeks, the fertilized egg attaches to the uterine wall, forming the placenta—a temporary organ that provides nutrition and gas exchange. Up to 10 weeks, we speak of an embryo. After that, we speak of a fetus, when the organ rudiments have formed and are growing and maturing. This distinction is important: the timing and expected ultrasound findings, as well as screening markers, differ. [8]

Amniotic fluid protects the fetus from injury and helps the lungs and digestive system develop according to the gestational age. The amount of amniotic fluid is assessed using ultrasound using the amniotic fluid index (AFI). The terms "oligohydramnios" and "polyhydramnios" describe abnormalities that require investigation and ongoing monitoring. [9]

Fetal movements are an important communication language. They typically become noticeable in the second trimester, and by 28 weeks, a recognizable rhythm should develop. Any noticeable decrease or absence of movements is a reason to seek immediate evaluation, as decreased activity may signal problems with the placenta or oxygen supply. [10]

In the third trimester, placental and umbilical cord blood flow is assessed using Doppler ultrasound, and fetal well-being is assessed using cardiotocography or a biophysical profile in those for whom it is indicated. These terms are often used in pregnancy management plans for those with risk factors and help guide timely decision-making. [11]

Screenings and tests by trimester: what each term means

The modern approach to dating and test selection relies on early ultrasound. In the first trimester, combined screening for chromosomal abnormalities is performed: nuchal translucency measurement by ultrasound plus biochemical markers in the blood. Non-invasive prenatal testing based on free fetal DNA in the mother's blood can be offered to all pregnant women, regardless of age, as a highly accurate screening option. [12]

In the second trimester, the key examination is a detailed ultrasound screening of the anatomy, which evaluates organs and structures and compares biometric measurements with the gestational age. Protocol terms are used here: biparietal diameter, head circumference, abdominal circumference, and femur length. Additional tests are prescribed if necessary. [13]

Between 24 and 28 weeks, carbohydrate metabolism is assessed, as gestational diabetes is often asymptomatic. A one-step or two-step approach is used depending on the country and clinic, but the meaning is the same: testing glucose tolerance and identifying abnormalities to prevent complications. [14]

At 36-37 weeks, screening for group B streptococcus is performed using a vaginal and rectal swab. Carriage itself is not a disease, but the term "intrapartum prophylaxis" refers to the administration of an antibiotic at the onset of labor to reduce the risk of early neonatal infection in the newborn. [15]

Table 2. Screenings and key tests

Period	Term	What does it mean?	Why is this necessary?
11-13 weeks 6 days	Combined screening	Ultrasound measurement of the nuchal translucency and blood for markers	Assessment of the risk of chromosomal abnormalities
From 10 weeks	Non-invasive prenatal testing	Analysis of free fetal DNA in maternal blood	More accurate screening of certain anomalies
18-22 weeks	Anatomical screening	Detailed assessment of fetal organs	Early detection of developmental anomalies
24-28 weeks	Glucose tolerance test	Assessment of carbohydrate metabolism	Diagnosis of gestational diabetes
36-37 weeks	Screening for group B streptococcus	Vaginal and rectal swabs	Prevention of early neonatal infection

Ultrasound and "those very words" in the conclusion

The crown-rump length is the main dating parameter in the first trimester, when the baby is still small and growing evenly. In the second and third trimesters, biometric dating is less accurate, so these measurements are used primarily to assess growth for gestational age. [16]

Biparietal diameter, head circumference, abdominal circumference, and femur length are basic growth indicators. The reports also include the amniotic fluid index and fetal position assessment. If any growth is delayed or advanced, the doctor compares it with the initial dating, medical history, and Doppler results. [17]

It's clear why even the simple term "placental position" is important. A low-lying placenta often "rises" as the uterus grows. The term "low-lying placenta" is used when the placental edge is closer to 20 mm from the internal os, and "placenta previa" is used when the placenta overlaps the os. This determines the strategy and possible method of delivery. [18]

Protocols periodically include "Doppler ultrasound of uteroplacental blood flow" and "cardiotocography" when monitoring high-risk groups. These terms describe how fetal well-being is assessed in the presence of risk factors for growth restriction, maternal hypertension, and other conditions. [19]

Table 3. Ultrasound terms in simple language

Term	When to use	What does it mean?
Parietal-coccygeal size	1st trimester	Accurate dating of pregnancy
Biparietal diameter, head circumference, abdominal circumference, femur length	2-3 trimesters	Assessment of growth and proportions
Amniotic fluid index	2-3 trimesters	Amount of amniotic fluid
Dopplerometry	According to the readings	Blood flow in the placenta and fetal vessels
Position of the placenta	Starting from the 2nd trimester	Mounting height and distance to the internal os

Placenta and Rh factor: what you need to know

A "low-lying placenta" is a common finding during mid-pregnancy screening and typically resolves by the third trimester. A repeat ultrasound around 32 weeks helps determine whether the placenta previa remains. Placenta previa in late pregnancy often requires a planned cesarean section. [20]

The term "placenta accreta" encompasses situations in which the placenta is excessively firmly attached to the uterine wall. The risk increases with the combination of placenta previa and a uterine scar from a previous cesarean section, and increases with the number of previous surgeries. These terms, when used in conjunction with the conclusion, indicate the need for management in a specialized hospital. [21]

Rh incompatibility is an immune response when the mother's blood is Rh-negative and the baby's blood is Rh-positive. Modern prophylaxis with anti-D immunoglobulin has dramatically reduced the risk of immune sensitization and hemolytic disease of the newborn. Routine antenatal prophylaxis is offered to all unsensitized Rh-negative women. [22]

The prophylactic regimen includes the administration of anti-D in the third trimester and after birth if the baby's Rh-positive status is confirmed, as well as after situations potentially associated with the entry of fetal blood into the maternal bloodstream. These terms in the chart refer to routine protection against antibody production. [23]

Table 4. Placenta and Rh factor

Term	Definition	What's next?
Low-lying placenta	The edge is closer than 20 mm to the internal os	Repeat ultrasound around 32 weeks
Placenta previa	Placental occlusion of the internal os	Delivery plan, often cesarean section
Placenta accreta	Excessive placental attachment to the myometrium	Management in a specialized center
Rhesus prophylaxis with anti-D	Administration of immunoglobulin to a Rh-negative mother	Reducing the risk of sensitization and hemolysis in the newborn

Onset of labor and labor pain: key terms

The latent phase is the period when the cervix softens and gradually dilates, with irregular contractions. The active phase is characterized by regular, painful contractions and progressive dilation. The term "false contractions" describes irregular contractions without progression of dilation. If contractions become regular or the water breaks, these are reasons for evaluation in the maternity ward. [24]

"Breaking of the mucus plug" and "leaking of amniotic fluid" are common reports in late pregnancy. The mucus plug may be lost days before labor begins. Leaking or breaking of membranes requires contacting the obstetrician to assess the timing and treatment. [25]

Pain relief methods during labor include non-pharmacological approaches, inhalation mixtures, opioid analgesics, and epidural analgesia. The term "epidural" refers to the delivery of anesthetic through a catheter into the epidural space of the spine, which is recognized as the most effective method of pain relief when monitoring standards are followed. [26]

The updates also mention "patient-controlled remifentanil" as an alternative in obstetric hospitals with required respiratory monitoring. The specific choice of pain relief always balances the preferences of the woman in labor, the indications, and the department's resources. [27]

Table 5. False and true contractions

Sign	False contractions	The onset of active labor
Rhythm	Irregular	Regular, increasing
Intensity	They get weaker with rest and warmth.	They get stronger and don't go away.
Localization of pain	Most often in the lower abdomen	Encircling, with spreading
Effect on the cervix	No progress in disclosure	Progressive disclosure

Table 6. Pain relief during labor

Method	What does it mean?	Peculiarities
Non-mendicant methods	Breathing, water, positions, massage	Reduced pain, improved control
Inhalation mixture	Gas mixture through a mask	Fast effect, controllability
Opioid analgesics	Intramuscularly or intravenously	Side effects may occur in mother and baby.
Epidural analgesia	Catheter in the epidural space	The most effective pain relief is with monitoring

Childbirth and the first minutes of life: terms in the delivery room

"Surgical vaginal delivery" is a birth performed using vacuum extraction or forceps when medically indicated. "Cesarean section" is an abdominal delivery, either planned or emergency. After a previous C-section, "vaginal birth after C-section" is possible if safety precautions are met. These terms are important for personalized planning. [28]

"Vaginal birth after cesarean" is a deliberate attempt to deliver the baby vaginally after a previous cesarean. This plan reduces the risks associated with multiple surgeries but requires the department to be prepared for emergency intervention. The choice between a repeat planned cesarean and an attempted vaginal birth depends on the chance of success and individual factors. [29]

"Delayed cord clamping" within the first minute or longer improves newborn hemodynamics and iron stores. "Skin-to-skin contact" and "early initiation of breastfeeding within the first hour" support adaptation and thermal balance. These terms in birth plans reflect the evidence-based benefits of simple actions. [30]

The Apgar score is a rapid assessment of a newborn's condition in the first and fifth minutes, based on five parameters. It is not a "lifelong health assessment," but a way to determine whether immediate intervention is needed. Average and low scores require medical attention in the first few minutes. [31]

Table 7. Terms in the delivery room

Term	Meaning	Clinical benefit
Vacuum extraction, forceps	Obstetric care during delivery of the fetal head	Reducing the time of the second period
C-section	Surgical delivery	Choice based on indications
Childbirth after cesarean section	Attempting vaginal birth after surgery	Less risk of multiple surgeries if successful
Delayed cord clamping	Waiting before clamping the umbilical cord	Better iron stores, transitional circulation
Skin-to-skin contact	Continuous contact on the parent's chest	Thermoregulation, attachment, start of lactation
Apgar scale	Rating in 1 and 5 minutes	A quick decision to help a newborn

When to seek urgent help: signal terms

"Decreased fetal movements," "leaking or rupture of amniotic fluid," "bloody discharge," "severe headache, flashing spots, and pain in the right upper quadrant with increased blood pressure" are markers that require immediate evaluation, especially in the third trimester. They are associated with a threat to the fetus or signs of preeclampsia. [32]

If the due date is close to the expected date and contractions are occurring regularly, every few minutes, the pain is increasing, bloody and mucous discharge appears, or the water has broken, a trip to the maternity ward is usually recommended. The exact route and timeframe for the appointment are individualized and discussed in advance in the birth plan. [33]

If the blood type is Rh-negative, any event with a risk of fetomaternal hemorrhage requires contacting the obstetric service for timely administration of anti-D, even outside the scheduled intervals. This reduces the risk of sensitization in the current and future pregnancies. [34]

Sugar overload, infections, hypertension, and other conditions have their own warning signs. Discuss your personal triggers during your next visit to avoid wasting time when symptoms arise. [35]

Table 8. Symptoms requiring urgent contact

Situation	Why is it important?	Who to report to
A sharp decrease in movements	Possible hypoxia, problems with the placenta	Obstetrics department immediately
Leakage or overflow of water	Risk of infection, hypoxia	Maternity ward for assessment
Bloody discharge	Possible placental pathology	Urgent assessment by an obstetrician
Severe headache, flickering, pain under the ribs on the right, pressure	Signs of preeclampsia	Urgent hospitalization

A brief glossary of commonly used English terms

Some of the reminders contain English words. Below are the correct Russian equivalents and their meanings.

• Non-stress test - resting cardiotocography for antenatal monitoring. Indicated for risk groups. [36]
• Cell-free DNA testing is a non-invasive prenatal test for free fetal DNA, available to all pregnant women as a screening method. [37]
• Group B Streptococcus screening - a smear test for group B streptococcus at the end of the third trimester. [38]
• Delayed cord clamping - delayed clamping of the umbilical cord in the first minutes. [39]
• Skin-to-skin contact - skin-to-skin contact in the first hour of life. [40]