Introduction

Lyme disease is an infectious disease caused by the bacteria Borrelia burgdorferi which is spread by ticks.¹ Lyme disease spreads to humans by the bite of infected black-legged ticks.² 

Lyme disease is a common tick-borne infections¹ but it is mostly diagnosed in Northeastern and upper Midwestern United States.¹ Lyme disease is endemic in the following states:¹ 

• Connecticut
• Delaware
• Maine
• Maryland 
• Massachusetts
• Minnesota
• New Hampshire
• Vermont
•  Wisconsin

Lyme disease is also found in the UK, with high-risk places including woodlands and grassy areas in northern and southern England and the Scottish Highlands. 

In these states, Lyme disease incidence rate is 40 per 100,000 people and infections occur during late spring, summer and early autumn.¹ Lyme disease affects all races and people of all ages but it is more common in persons assigned female at birth (PAFB).¹ 

Lyme disease is characterised by a skin rash called erythema migrans, followed by fever, headache and fatigue.² If Lyme disease is not treated, the bacterial infection can spread to other parts of the body like the joints, heart and nervous system, leading to complications.² 

Lyme disease whilst pregnant can cause some complications for both the mother and the unborn foetus. This can include infections in the placenta, birth defects and stillbirth.³ There is no evidence that the foetus can become infected with Lyme disease from the mother, but risks can be caused by untreated Lyme disease.⁴

Understanding the risks of Lyme disease to ensure maximum health of the mother and foetus is important. Understanding the risks allows for early intervention in treating Lyme disease and preventing complications that can risk the mother's health and prevent birth defects. 

Lyme disease and its transmission

Lyme disease is caused by a bacteria called Borrelia burgdorferi in the United States and by Borrelia burgdorferi, Borrelia afzelii and Borrelia garinii¹ in Europe and Asia.

The bacteria is transmitted by the bite of an infected tick belonging to the Ixodes family, usually the Ixodes scapularis.¹ 

Ticks can be found all year round, but they are most active in the warmer months, from April to July.⁵ Ticks are found in grassy and woodland areas but can live in many outdoor environments and most bites occur when individuals are hiking, cycling or camping.⁵ Ticks are also found in areas with abundant livestock like horses or cows, and wild animals like deer.⁵ Ticks can also be found in urban parks and gardens and tick bites may occur there too.⁵ 

Symptoms of Lyme disease

Lyme disease infection can be split into three stages:¹

1. Early localised
2. Early disseminated
3. Late 

First stage: early localised

The first presenting symptom of Lyme disease is the erythema migrans rash which is present in 70% to 80% of cases.¹ Erythema migrans is a spreading red rash that begins as a small red spot at the site of the bite which expands over time to form a circular, oval-shaped or triangular rash.⁴ The rash looks like a bullseye with the tick bite being the centre and this rash occurs 3 to 30 days after a bite.⁵ Erythema migrans can range in size from a coin size to covering the entirety of a patient's back.⁴ If Lyme disease is left untreated and the infection spreads, there could be several erythema migrans at several sites on the body.⁴

Other symptoms in the first stage can include⁴

• Fever
• Headache
• Body and joint aches
• Stiff neck
• Fatigue
• And swollen lymph nodes 

Second stage: early dissemination

Most patients only experience the first stage of Lyme disease, but 20% of patients develop early dissemination.¹ Second stage develops 3 to 12 weeks after tick bite and the symptoms could last for 12 to 20 weeks.¹

Early dissemination of Lyme disease can cause the following symptoms:⁴

• Multiple erythema migrans around the entire body
• Heart block that interrupts the electrical activity of the heart 
• Paralysis of the facial muscles 
• Neuropathy where there are areas of numbness or abnormal feeling

Third stage: late 

Late stage of Lyme disease can occur months or years year after tick bite¹ and symptoms can include:⁴

• Arthritis (swollen joints) that is recurring and affects mainly large joints like the knee
• Damage to nerves all around the body including the muscles, skin, and organs
• Patients also struggle with concentrating and this is due to damage to the brain 

Risks of Lyme disease during pregnancy

As discussed earlier, Lyme disease can cause complications in pregnant PAFB and can affect both the mother's and the foetus’s health. However, there are limited studies that have investigated the direct effect of Lyme disease during pregnancy and more studies are required to fully understand how Lyme disease impacts pregnancy. 

Effects on a pregnant person assigned female at birth³

Lyme disease that is not treated can cause complications for the mother and these can include:

• Can cause stillbirths - this is where the foetus dies after the 20th week of pregnancy
• Miscarriages can also occur
• Vaginal bleeding⁶
• Extreme tiredness⁶
• Irritable uterus (where there is uncomfortable contraction)⁶
• And gestational diabetes⁶ (where there is an elevated glucose level in the blood during pregnancy)

Alongside these complications, pregnant PAFB are also at higher risk of developing severe symptoms like fever, headaches and muscle aches. 

Effects on the foetus

Lyme disease can affect the foetus and cause the following complications:

• Congenital heart defects can affect the foetus’s heart and how it works³
• Urinary tract defects where there is a blockage urinary tract including the kidney and bladder can lead to pain, urinary tract infection and kidney failure³
• Hyperbilirubinemia is when there is a build-up of bilirubin in the blood that causes the baby to develop jaundice. Jaundice is when the baby's skin and eyes turn yellow and this is caused by the kidney working fully.³
• Respiratory distress^,6 where there is fluid leaking into the lungs and this is a life-threatening condition
• Cleft lip and palate⁶ 
• Rashes on skin⁶

The effect Lyme disease has on the mother and foetus depends on if Lyme disease is treated.⁶ Complications are more severe for both mother and foetus when Lyme disease is left untreated and the disease is allowed to progress. 

Diagnosis of Lyme disease in a pregnant person assigned female at birth

Lyme disease is diagnosed by a combination of observation and lab testings² and this is the same for pregnant PAFB:

1. Doctors or health professionals will observe the signs and symptoms you are presenting
2. Take a medical history and ask questions about lifestyle choices - do you go hiking or any outdoor activities where you are exposed to black-legged ticks?
3. Take laboratory tests that test the blood for the presence of bacteria

Laboratory testing

Many people don’t remember getting bit by a tick as the bite is painless and thus most diagnosis is dependent on blood tests.⁴ ELISA and western blot are common techniques used to detect antibodies present in the blood against the bacteria.³ Health professions will take two positive results to diagnose patients with Lyme disease.⁴ 

It is important to detect Lyme disease early on in pregnant women as early diagnosis means better management and outcomes for both mother and foetus.⁶ Severe complications caused by Lyme disease are found in untreated Lyme disease and early diagnosis will prevent these complications, hence improving the outcome of Lyme disease in pregnancy. 

Treatment options for a pregnant person assigned female at birth

Lyme disease is treated by antibiotics but safe antibiotics are needed for pregnant women to prevent side effects in the foetus. Safe antibiotics given to pregnant PAFB to treat Lyme disease include:

• Amoxicillin 
• Tetracyclines⁶
• Cephalosporins⁶ 
• Penicillins⁶
• Azithromycin⁶

Most pregnant PAFBs have good results with ceftriaxone.¹ Antibiotic therapy may last as long as four weeks and most women who take antibiotics give birth to healthy babies.³

Alongside antibiotics, pregnant PAFB has increased monitoring and regular medical checkups to make sure that both mother and foetus are healthy.

Precautions to prevent Lyme disease during pregnancy

The best and only way to prevent Lyme disease during pregnancy is to prevent being bitten by ticks and here are the following steps to prevent it:

1. Stay away from wooded areas and grassy lands as these are tricky places of habitat 
2. Use bug spray to repel ticks but pregnant women must be careful when using these as too much can be harmful to the baby and the mother⁴
3. Wear long-sleeved tops and long trousers that are tucked into socks and shoes, alongside a hat to prevent ticks from biting if venturing into areas where ticks are known
4. Pets can also bring ticks into the house, so managing pets is important to prevent ticks from biting you 

Summary

Lyme disease is an infectious disease caused by the bacteria Borrelia burgdorferi which is spread by ticks.¹ Ticks can be found all year round, but they are most active in the warmer months.⁵ Ticks are found in grassy and woodland areas but can live in many outdoor environments and most bites occur when individuals are hiking, cycling or camping.⁵ Lyme disease infection can be split into three stages: early localised, early disseminated and late. The first presenting symptom of Lyme disease is the erythema migrans rash which is present in 70% to 80% of Lyme disease cases. Lyme disease can cause complications in pregnant PAFB and can affect both the mother's and the foetus's health. It can cause mothers to lose their babies and suffer from severe symptoms and can cause developmental problems in the foetus. Complications associated with Lyme disease become more severe if Lyme disease is left untreated and therefore early diagnosis and effective treatment is needed to prevent these complications. Seeking medical advice is crucial for pregnant PAFB who believe they may have Lyme disease, to improve outcomes for both the mother and the foetus.