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What is Intrauterine Pregnancy?

Understanding intrauterine pregnancy stages ensures a healthy start.

9. February 2024
Last Modified
14. February 2024

Today we will explore intrauterine pregnancy. It explores key stages, highlights early signs, and explains how to differentiate from ectopic pregnancies. It also tackles complex cases like IPUV and emphasises the importance of early prenatal care. With expert care and diagnostics, the London Pregnancy Clinic supports mothers throughout this life-changing journey. 

Intrauterine pregnancy marks the beginning of an incredible journey, not just for the embryo that grows and develops within the uterus but also for expectant mothers who embark on a nine-month journey filled with anticipation, joy, and care. For many, understanding the nuances of intrauterine pregnancy offers reassurance and clarity about the changes their bodies undergo and the milestones their future child achieves even before birth.

What is intrauterine pregnancy?

An intrauterine pregnancy (IUP) occurs when a fertilised egg successfully travels down the fallopian tube, implants in the uterine lining, and develops into an embryo, fetus, and eventually a baby. This natural process is the foundation of a normal 3 trimester pregnancy journey. 

First Trimester: It is crucial, as it sets the foundation for the baby’s development. It’s when the heart begins to beat, and the basic structures of the body start forming. Understanding the significance of early prenatal care during this stage is vital for expectant mothers to support their baby’s health.

Second Trimester: As the pregnancy progresses into the second trimester, mothers can feel their baby’s first movements—a magical moment for many. This period focuses on the baby’s growth, with vital organs continuing to develop and facial features becoming more distinct.

Third Trimester: The final stretch of the intrauterine journey involves the baby gaining weight and the body preparing for delivery. It’s a time for mothers to focus on nutrition and self-care, ensuring they’re ready for the birthing process.

Signs and Symptoms of IUP

Recognising the early signs and symptoms of intrauterine pregnancy is crucial for expectant mothers. These include missed periods, tender breasts, fatigue, and mood changes. While these indicators do not guarantee the pregnancy’s location, they are the first clues that you might be embarking on the journey of motherhood. However, symptoms like abnormal bleeding, pelvic pain, and cramping on one side may indicate an ectopic pregnancy, necessitating prompt medical evaluation.

While early pregnancy symptoms are similar regardless of the pregnancy’s location, certain developments confirmed via ultrasound are specific to intrauterine pregnancies:

  • Visualisation of the Gestational Sac: A fluid-filled sac surrounding the embryo, visible via transvaginal ultrasound as early as 4 weeks of pregnancy.
  • Embryonic or Fetal Heartbeat: Detected by ultrasound, a heartbeat within the uterus confirms an intrauterine pregnancy, usually visible around 6 weeks of pregnancy.
  • Fetal Movement: Felt by the mother as the pregnancy progresses, typically starting between 18 to 22 weeks for first-time mothers. However, some mothers may not recognise these initial flutters or any other pregnancy symptoms during this period, leading to a phenomenon known as cryptic pregnancy. In cryptic pregnancies, the signs of being pregnant remain unnoticed until the later stages, often until the baby’s movements become unmistakably strong or other more overt pregnancy symptoms emerge. This can result in a delayed awareness of pregnancy, making early prenatal care and emotional preparation more challenging.

Please note that this response does not constitute medical advice. If you have concerns or questions about pregnancy, consult a qualified healthcare professional.

Image showing a intrauterine pregnancy at 4 weeks of pregnancy on ultrasound. It shows an Ultrasound image by London Pregnancy Clinic that shows the gestational sac and how small it is - for educational purpose.
Intrauterine pregnancy at 4 weeks of pregnancy on ultrasound.
Image showing Intrauterine pregnancy at 7 weeks of pregnancy on ultrasound. It shows an Ultrasound image by London Pregnancy Clinic that shows the gestational sac, fetal pole and yolk sac - for educational purpose.
Intrauterine pregnancy at 7 weeks of pregnancy on ultrasound.

Intrauterine pregnancy of uncertain viability (IPUV)

Understanding the early stages of pregnancy is vital for expectant mothers. When diagnosed with an early intrauterine pregnancy, it means that a pregnancy sac is present in the womb. However, it might be too soon to visualise the baby or detect a heartbeat. This stage can also be described as a “pregnancy of uncertain viability” (IPUV), highlighting the period of anticipation and monitoring that follows.

Early Stage of Pregnancy: The pregnancy is simply at its beginning phases, necessitating more time for growth to see the embryo and heartbeat. This scenario is more probable if there’s uncertainty about your menstrual dates, you experience irregular periods or have recently ceased using contraceptive measures. In these instances, the alignment between expected and actual pregnancy stages may not be precise, requiring patience and subsequent evaluations.

Potential Non-Progression: There’s a chance the pregnancy isn’t advancing as anticipated. This likelihood increases if you’re confident about your pregnancy dates, yet they don’t align with the observed size of the pregnancy sac. Additional indicators suggesting potential non-progression include experiencing vaginal bleeding or having a low progesterone level. In such cases, close monitoring and further diagnostic testing are essential to determine the pregnancy’s viability and appropriate next steps.

For expectant mothers facing an IPUV diagnosis, the uncertainty can be challenging. However, with compassionate care and comprehensive monitoring, many uncertainties can be resolved as the pregnancy progresses. Follow-up ultrasounds and blood tests play a pivotal role in clarifying the viability of the pregnancy, guiding both medical professionals and mothers-to-be in their journey towards a healthy pregnancy outcome.

Confirming pregnancy early is crucial

The detection of IPUV or ectopic pregnancy underscores the importance of early prenatal care. Early prenatal care is instrumental in monitoring the health of both the mother and the baby. Regular check-ups can detect any potential issues early on, providing a pathway for interventions if necessary. This proactive approach is key to managing a healthy pregnancy. Thus, identifying the pregnancy location early is crucial, especially to differentiate it from ectopic pregnancies and avoid misdiagnosis. You can do so in a few ways:

  • Urine Tests: Detect hCG typically one day after a missed period, with accuracy increasing over time.
  • Blood Tests: Measure levels of the pregnancy hormone hCG, detecting pregnancy as early as 6–8 days post-ovulation. Increasing levels of hCG can indicate that the pregnancy is progressing normally, while stagnant or decreasing levels may suggest complications.
  • Follow-up Ultrasound: An ultrasound can visualise a gestational sac around the embryo in the uterus, definitively confirming an intrauterine pregnancy. If an IPUV is diagnosed, expectant mothers will typically be scheduled for follow-up ultrasounds. These are crucial to assess the pregnancy’s progress. The timing of these follow-ups can vary but usually occurs within 1-2 weeks to allow sufficient time for any changes to be evident.
  • Patient Guidance: Healthcare providers will offer advice on what symptoms to watch for and when to seek immediate medical attention. This might include severe abdominal pain, increased vaginal bleeding, or any signs of infection.

Intrauterine Pregnancy FAQs

Is intrauterine pregnancy is good or bad?

Intrauterine pregnancy is not only normal but also the optimal outcome for a successful pregnancy, where the fertilised egg implants and grows within the uterus. This condition is crucial for the fetus’s healthy development, representing a positive and expected part of a woman’s reproductive experience. While certain complications can affect fetal growth within the womb, these issues are distinct from the nature of intrauterine pregnancy itself.

Difference between intrauterine pregnancy and ectopic?

The primary distinction between an intrauterine and an ectopic pregnancy centers on the location of implantation. In a healthy intrauterine pregnancy, the fertilized egg secures itself within the uterus, the optimal site for a fetus to grow and mature. Conversely, in an ectopic pregnancy, the egg implants outside the uterus, often in a fallopian tube, though it can also occur in the ovary, cervix, or abdominal cavity. This misplaced implantation can lead to severe health risks, including the potential for rupture and internal bleeding, as the fetus cannot properly develop in these locations, endangering the mother’s well-being.

Can intrauterine pregnancy survive?

An intrauterine pregnancy, where the fertilised egg implants and grows within the uterus, represents the standard and healthiest form of pregnancy, crucial for the fetus’s healthy development. Unlike ectopic pregnancies, which occur outside the uterus and pose significant health risks, intrauterine pregnancies are both sustainable and desired. These pregnancies have the potential to proceed to full term, leading to the birth of a baby. Therefore, an intrauterine pregnancy is not only capable of surviving but is also the optimal scenario for both fetal development and maternal health.

What are the Early Stage Considerations for IPUV

In cases where there’s uncertainty about menstrual dates or if a patient has irregular periods, the exact timing of early pregnancy events may not align with standard expectations. It’s also common for women who have recently stopped using contraceptive methods to experience variability in their cycle lengths, affecting the dating of the pregnancy.

If the pregnancy is indeed at a very early stage, subsequent ultrasounds can provide reassurance as the embryo becomes visible and a heartbeat can be detected.


Understanding and early detection of intrauterine pregnancy are critical for ensuring the safety and health of both the mother and the developing baby. If you’re pregnant or planning to conceive, it’s essential to seek early prenatal care. Here at London Pregnancy Clinic, we offer comprehensive support and advanced diagnostic services to guide you through your pregnancy journey.

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