Placenta Previa and Low-Lying Placenta: What Expecting Mothers Need to Know
By Dr Greg Jenkins | Sydney-based specialist in Fertility, Obstetrics and Gynaecology
During pregnancy, the placenta plays a vital role in supporting your baby’s growth, supplying oxygen and nutrients throughout the journey. In some pregnancies, the placenta lies lower than usual in the uterus, sometimes covering the cervix. This is known as placenta previa or a low-lying placenta. While this can sound concerning, careful monitoring and planning usually lead to safe outcomes for both mother and baby.
Understanding Placenta Previa and Low-Lying Placenta
The placenta normally attaches to the upper wall of the uterus, away from the cervix. In placenta previa, it lies low, partly or completely covering the cervical opening. A low-lying placenta sits close to the cervix but not over it.
This condition is usually identified during a routine ultrasound at 18–20 weeks, known as the morphology scan. Most of the time, the placenta naturally moves upward as the uterus grows, resolving before the later stages of pregnancy.
However, when the placenta remains low, it requires extra monitoring and a clear delivery plan to ensure safety during birth.
Types of Placenta Previa
There are several types, classified based on how much of the cervix is covered:
Complete previa: The placenta completely covers the cervix.
Partial previa: The placenta partially covers the cervix.
Marginal previa: The placenta reaches the edge of the cervix but does not cover it.
Low-lying placenta: The placenta sits within two centimetres of the cervix but not over it.
These distinctions help guide decisions around follow-up, delivery timing and mode of birth.
Causes and Risk Factors
Placenta previa can occur in any pregnancy, but some factors make it more likely. These include:
Previous caesarean section or uterine surgery
Multiple pregnancies (such as twins or triplets)
Placenta previa in a previous pregnancy
Maternal age over 35
Smoking or previous uterine infection
While none of these automatically mean placenta previa will develop, they help guide obstetricians in identifying women who need closer monitoring. In fact most women with placenta do not have any of these risk factors.
Recognising Symptoms and When to Seek Help
The most common symptom of placenta previa is painless vaginal bleeding, usually in the second or third trimester. The bleeding may range from light spotting to heavier flow.
If you experience any vaginal bleeding during pregnancy, even if it seems minor, it’s important to contact your healthcare provider or go straight to hospital. Avoid internal examinations or intercourse until the cause is confirmed, as these can worsen bleeding when the placenta is low.
Other warning signs may include early contractions or reduced baby movements, both of which also need review.
Monitoring and Ongoing Care
Once a low-lying placenta is detected, follow-up ultrasounds are key. These typically occur around 28 and 34 weeks to check whether the placenta has moved upward as the uterus expands.
If it remains low, your obstetrician will monitor you more closely. Some women may be advised to avoid strenuous activity, heavy lifting, or travel, particularly if bleeding has occurred.
In more serious cases or repeated bleeding episodes, hospital admission may be recommended for rest and observation.
At every stage, the goal is to balance safety with maintaining as normal and comfortable a pregnancy as possible.
Delivery Planning
When placenta previa persists into the third trimester, a caesarean section is usually the safest option for delivery. This is generally planned for around 37–38 weeks, before labour begins naturally, to reduce the risk of bleeding.
Your obstetrician will discuss:
Timing of delivery
The hospital setting, ensuring surgical and neonatal teams are on standby
Women with mild or marginal low-lying placentas may still be able to have a vaginal birth if the placenta has moved far enough away from the cervix, but this decision is always guided by safety.
Emotional Support and Reassurance
Being told your placenta is low can understandably cause worry. However, with modern monitoring and obstetric planning, outcomes are overwhelmingly positive. Most women with placenta previa deliver healthy babies.
It helps to focus on regular check-ups, open communication with your care team, and having a clear plan for delivery. Many women find peace of mind by understanding exactly what to expect and knowing their care is being closely guided by an experienced team.
Final Thoughts
Placenta previa and low-lying placenta require extra attention, but they are conditions that obstetricians manage safely every day. Early detection, clear communication, and personalised planning are the key factors that ensure healthy outcomes for both mother and baby.
If you have been told you have a low-lying placenta, stay in close contact with your obstetrician and attend all follow-up scans. With careful monitoring and support, you can look forward to a safe delivery and a positive birth experience.
Meet Dr. Greg Jenkins: Your Partner in Fertility and Obstetrics
Dr Greg Jenkins is a specialist obstetrician, fertility specialist and gynaecologist, and the Head of Obstetrics and Gynaecology at Westmead Public Hospital. He provides personalised care for women and couples across fertility treatment, pregnancy and birth — with the unique advantage of continuity of care from conception through to delivery.
Dr Jenkins consults privately at Norwest Private Hospital in Bella Vista and works in partnership with Minerva Fertility at Bond Day Hospital. He offers delivery at Norwest Private, Westmead Private and Westmead Public Hospital, giving families flexibility in choosing the setting that best suits their needs.
