Background: A small proportion of cases of recurrent pregnancy loss are associated with identifiable causes in the mother or fetus, but the underlying cause in most of cases remains unknown.

Objective: Assessment of safety and efficiency of anticoagulant therapy in treating cases of recurrent miscarriage with negative antiphospholipid antibodies.

Methods: This study was conducted on 80 women with recurrent miscarriage without diagnostic criteria of anti-phospholipid syndrome (APS). Cases were randomly enrolled and divided into two equal groups to receive one of the following treatments once fetal heart activity was detected by ultrasound; study group received low dose aspirin till 36 weeks of gestation plus low molecular weight heparin (LMWH) till the end of pregnancy and control group received low dose aspirin alone till 36 weeks of gestation. Continuation of viable pregnancy beyond 20 weeks of gestation, live birth rate, miscarriage rate occurrence of pregnancy complications and any maternal or fetal side effects of used medications were compared between both groups.

Results: there were no statistically significant differences between study groups regarding fetal and maternal outcomes as fetal viability at all visits, incidence of fetal anomalies or still birth, mode of delivery, drug-related adverse events and incidence of preterm delivery. On the other hand, the gestational age at delivery was significantly higher and the incidence of NICU admission and neonatal death were significantly lower in the aspirin plus LMWH compared with the aspirin only group.

Conclusion: Combination of aspirin and LMWH was more effective than aspirin alone in decreasing the incidence of miscarriage in the first 20 weeks of pregnancy and the incidence of postpartum NICU admission and neonatal death in women with unexplained recurrent pregnancy loss.

Recurrent miscarriage, also known as recurrent pregnancy loss (RPL), is traditionally defined as three or more consecutive miscarriages before the 20th week of pregnancy (1).

Recurrent pregnancy loss is a major women's health issue; 1% to 2% of reproductive-age women have lost three or more consecutive pregnancies, and approximately 5% have lost at least two consecutive pregnancies (2).

A small percentage of these losses are due to identifiable causes in the mother or fetus, but the underlying cause in the majority of cases of recurrent pregnancy loss is unknown (3).

The antiphospholipid antibodies syndrome is linked to recurrent abortions and pregnancy complications such as intrauterine growth restriction (IUGR), preterm labor, preeclampsia, and intrauterine foetal death (IUFD) (4).

The negative effects of antiphospholipid antibodies on trophoblast differentiation and invasion, placental infarctions, and thrombosis are thought to be the cause of recurrent abortion and pregnancy complications associated with APS (5).

Few clinical trials have looked at the role of heparin in the treatment of patients with RPL but no APA. These studies discovered that patients with APS-like symptoms who tested negative for lupus anticoagulant (LAC) and anticardiolipin (aCL) antibodies were carrying pregnancy-harming antibodies (6).

In a randomised prospective trial, the efficacy of early thromboprophylaxis with low-molecular-weight heparin (LMWH) in women with recurrent miscarriage without identifiable causes was investigated. The findings revealed that the rate of both early and late miscarriages has significantly decreased (7).

This randomized controlled comparative clinical trial was conducted on 80 women with recurrent miscarriage attended Ain Shams University Maternity Hospital between May and August 2022.

Inclusion criteria

Pregnant women aged 20-35 years old, with a history of 2 or more spontaneous consecutive miscarriages before 20 weeks’ gestation, gestational age 6-8 weeks, regularly menstruating before current pregnancy, and get spontaneous conception without diagnostic criteria of APS were enrolled.

Exclusion criteria

Women with polycystic ovarian syndrome, any endocrinal abnormalities such as diabetes mellitus, thyroid disorders, history of abnormal uterine cavity proved by hysterosalpingiography, sonohysterography or hysteroscopy before pregnancy, positive consanguinity, thrombocytopenia (<100>

Randomization

Patients were randomized using sequentially sealed opaque envelope method into two and randomization was guided by a table of random members by a computer-based program (using www.randomization.com).

Allocation and concealment

The women were assigned to study arms using sealed, opaque envelopes that were given to a third party (nurse). Each lady was asked to select an envelope. Women were assigned to groups 1 or 2 according to a computer-generated random list based on the number inside their envelopes.

Study procedures 

All eligible participants were recruited to receive one of the following treatments once fetal heart activity was detected by ultrasound. Group I "aspirin alone group" "control group" took acetyl salicylic acid orally (Aspocid® 75mg tablet, CID, Egypt) once daily as soon as fetal heart activity was detected by ultrasound till 36weeks and group II "aspirin plus LMWH group" "study group" took acetyl salicylic acid orally (Aspocid® 75mg tablet, CID, Egypt) till 36 weeks plus enoxaparin sodium (Clexane® injection, Sanofi, France) subcutaneous injection according to body weight1 mg per kg once daily as soon as fetal heart activity was detected by ultrasound till the end of pregnancy.

All study participants were followed up on until the end of their pregnancy using the standard antenatal care frequency that pregnant women receive in obstetrics clinics.

At 6 weeks after their last menstrual period, each participant had a transvaginal scan to determine foetal viability. Two more trans-abdominal scans were performed around the 10th and 20th weeks of pregnancy.

The patients' antenatal data, including foetal viability and any other difficulties, were kept up until the delivery.

Before obtaining written informed consent, all patients were subjected to an explanation of the study procedure, a full history taking including detailed previous obstetric and gynaecological histories, a complete clinical examination, and a trans abdominal ultrasound to confirm foetal viability at the 6th, 10th, and 20th weeks of gestation.

Laboratory investigations was done as follows; 10 ml of venous blood was drawn from all patients before joining research study; 2 ml in EDTA tube for CBC and blood group, 3 ml in serum separation tube for blood sugar and hepatitis B surface Ag and hepatitis C virus, 3ml in citrate tube for bleeding time, clotting time, prothrombin time, activated partial thromboplastin time and 2ml in chemistry tube (Anti Cardiolipin IgG, Anticardiolipin IgM, Anti B2 glycoprotein IgG , Anti B2 glycoprotein IgM, Lupus anticoagulant)by an enzyme-linked immunosorbent assay for APAs. The results were considered positive when the aCL-IgG >8.4 IU/Ml and aCL-IgM >7 IU/mL.

Pain and bruising at injection sites were also reported as side effects of LMWH use.

The current study's primary endpoint was the continuation of a viable pregnancy beyond 20 weeks of gestation. Secondary outcomes included the live birth rate, miscarriage rate, and occurrence of pregnancy complications such as IUGR or preeclampsia, as well as any drug-related side effects such as maternal bleeding, heparin-induced thrombocytopenia, pain and bruising at injection sites.

Statistical Analysis

The statistical analysis was carried out using MedCalc® Statistical Software version 20 (MedCalc Software Ltd, Ostend, Belgium; https://www.medcalc.org; 2021) and IBM SPSS Statistics version 23 (IBM Corp., Armonk, NY). Intergroup differences were compared using the Pearson chi-squared test or Fisher's exact test, and categorical variables were shown as counts and percentages. Chi-squared tests for trend were used to compare ordinal data. The independent-samples t-test was used to examine group differences in continuous numerical variables provided as mean and standard deviation. The Kaplan-Meier method was used for time-to-event analysis, and the Logrank test was applied to compare various Kaplan-Meier curves. P-values lower than 0.05 were regarded as statistically significant.

There was no statistically significant difference between two groups regarding age, gravidity, and frequency of previous abortions, number of living children, history of previous surgery or ABO/Rh blood group (all p-values > 0.05) (Table 1).

Table 1: Comparison between study and control groups regarding demographic data:

There was no statically significant difference in the results of sonographic studies between both groups (all p-values > 0.05) (Table 2).

Table 2: Sonographic studies:

There was no statically significant difference between both groups as regards AFI (all p-values > 0.05) (Table 3).

Table 3: AFI:

All patients had viable babies at the three follow-up visits as well as at 20 weeks of gestation in either group. Also, it showed that there were no fetal anomalies in both research study groups (Table 4).

Table 4: Fetal viability and fetal anomalies:

Gestational age at delivery was significantly higher in the aspirin plus LMWH compared with the aspirin only group (36.5 ± 1.7 weeks versus 35.5 ±2.1 weeks, respectively, p-value = 0.026) However, the incidence of pre-term delivery was comparable in both groups (45.0% versus 62.5%, respectively) (Table 5).

Table 5: Gestational age at delivery:

Incidence of NICU admission and neonatal death were significantly lower in the aspirin plus LMWH compared with the aspirin only group (30.0% versus 55.0%, p-value = 0.024 and 17.5% versus 40.0%, p-value = 0.026, respectively) (Table 6).

Table 6: NICU admission and NICU death:

The addition of LMWH to aspirin was associated with a statistically significant reduction in the risk of NICU admission (RR = 0.55, 95% CI = 0.31 to 0.95, p-value = 0.031) and neonatal death (RR = 0.44, 95% CI = 0.20 to 0.95, p-value = 0.036) with a number needed to treat (NNT) of 4 (95% CI = 2.18 to 24.76) patients and 4.44 (95% CI = 2.40 to 30.43) patients, respectively (Table 7).

Table 7: Addition of LMWH to aspirin and the risk of NICU admission:

The current study contradicted a recent meta-analysis conducted by Yan et al, who found that, when compared to the control group, both LMWH and LMWH + aspirin therapies had no significant effect on miscarriage rate and the prevalence of pre-eclampsia. LMWH medication had no effect on live births. Enoxaparin is ineffective in women with uRM and negative aPL, according to subgroup analysis (8).

Jiang et al, on the other hand, conducted a systematic review and meta-analysis in 2021 and proposed that LMWH could increase RPL live births and decrease RPL miscarriage rates (9).

In addition, Shaaban et al concluded that LMWH reduces miscarriage in the early half of pregnancy in women with unexplained RM who are negative for APAs. When compared to the control group, there was a significant increase in women who prolonged their pregnancy through 20 weeks in the study group. The LMWH group also had a significantly higher take-home baby rate than the control group (10).

The current study supported the findings of AbdElfattah et al, who found that low-dose aspirin (aspocid 75mg tab) and LMWH (clexane 1 mg/kg) improve pregnancy outcome and increase live-birth rate, with no significant differences between the two drugs in patients with a history of recurrent miscarriages who did not have antiphospholipid antibody syndrome. Both medicines enhanced the live-birth rate, with 81.7% in group 1 and 83.3% in group 2 (11).

We agreed with Maged et al, who discovered that using prophylactic doses of calheparin and aspirin is associated with an increased chance of safely passing the first trimester regardless of age, BMI, or number of abortions in women with unexplained recurrent spontaneous abortion. There was a statistically significant difference in the number of patients who completed their first trimester between the two study groups (66 versus 39) (12).

Zhang et al. disagreed with our findings and opposed the use of combined low molecular weight heparin and aspirin for RM treatment, claiming that aspirin may have a negative effect on lowering the risk of pregnancy loss (13).

Elmahashi et al. concurred with our findings, concluding that the combination of low dose aspirin (LDA) and LMWH is superior to LDA alone for pregnancy maintenance in patients with recurrent first trimester miscarriage. Compared to the LDA-only group, the combination group had significantly fewer miscarriages (22/75 [29%] vs. 43/75 [47%], P 0.001) and significantly more live births (53/75 [71%] vs. 32/75 [42%], P 0.001) (3).

de Jong et al disagreed with us and concluded that there were few studies on the efficacy and safety of aspirin and heparin in women with at least two unexplained miscarriages, with or without inherited thrombophilia. Anticoagulants had no beneficial effect in studies with a low risk of bias (14).

Finally, Begum et al. disagreed with us and found that low molecular weight heparin therapy was effective. Pregnancy was successfully continued in 96.66% of cases (15).

This study found that starting aspirin plus LMWH early in pregnancy reduces the risk of miscarriage, postpartum NICU hospitalisation, and infant death in women with unexplained recurrent pregnancy loss who are negative for antiphospholipid antibodies. Furthermore, the combination of aspirin and LMWH was more effective than aspirin alone, with no observed side effects. As a result, our findings pave the way for more research into the role of aspirin plus LMWH in the treatment of unexplained recurrent pregnancy loss in women with negative antiphospholipid antibodies.

Acknowledgments 

Authors would like to thanks to Ain Shams University and the patients recruited in the study.

Funding: No funding sources 

Conflict of interest: None declared 

Ethical approval: The study was approved by the Institutional Ethics Committee